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Li, W.; Tong, W.; Yadav, A.; Bladt, E.; Bals, S.; Funston, A.M.; Etheridge, J. |
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Title |
Shape control beyond the seeds in gold nanoparticles |
Type |
A1 Journal article |
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Year  |
2021 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
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Volume |
33 |
Issue |
23 |
Pages |
9152-9164 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
In typical seed-mediated syntheses of metal nanocrystals, the shape of the nanocrystal is determined largely by the seed nucleation environment and subsequent growth environment (where “environment” refers to the chemical environment, including the surfactant and additives). In this approach, crystallinity is typically determined by the seeds, and surfaces are controlled by the environment(s). However, surface energies, and crystallinity, are both influenced by the choice of environment(s). This limits the permutations of crystallinity and surface facets that can be mixed and matched to generate new nanocrystal morphologies. Here, we control post-seed growth to deliberately incorporate twin planes during the growth stage to deliver new final morphologies, including twinned cubes and bipyramids from single-crystal seeds. The nature and number of twin planes, together with surfactant control of facet growth, define the final nanoparticle morphology. Moreover, by breaking symmetry, the twin planes introduce new facet orientations. This additional mechanism opens new routes for the synthesis of different morphologies and facet orientations. |
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000753956100012 |
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0000-00-00 |
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0897-4756; 1520-5002 |
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UA library record; WoS full record; WoS citing articles |
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Impact Factor |
9.466 |
Times cited |
3 |
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Not_Open_Access |
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Notes |
This work was supported by the Australian Research Council (ARC) Grants DP160104679 and CE170100026 and used microscopes at the Monash Centre for Electron Microscopy funded by ARC Grants LE0454166, LE110100223, and LE140100104. W.L. thanks the support of the Australian Government Research Training Program (RTP) scholarship. W.T. thanks the Australian Department of Education and Monash University for the IPRS and APA scholarships. E.B. acknowledges financial support and a post-doctoral grant from the Research Foundation Flanders (FWO, Belgium). The authors thank Dr. Matthew Weyland and Dr. Tim Peterson for helpful discussions. A.Y. thanks the support from Post Graduation Publication Award (PPA) scholarship from Monash University. |
Approved |
Most recent IF: 9.466 |
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Call Number |
UA @ admin @ c:irua:187229 |
Serial |
7065 |
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Author |
Li, C.; Tardajos, A.P.; Wang, D.; Choukroun, D.; Van Daele, K.; Breugelmans, T.; Bals, S. |
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Title |
A simple method to clean ligand contamination on TEM grids |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
221 |
Issue |
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Pages |
113195 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
Colloidal nanoparticles (NPs) including nanowires and nanosheets made by chemical methods involve many organic ligands. When the structure of NPs is investigated via transmission electron microscopy (TEM), the organic ligands act as a source for e-beam induced deposition and this causes substantial build-up of carbon layers in the investigated areas, which is typically referred to as “contamination” in the eld of electron mi- croscopy. This contamination is often more severe for scanning TEM, a technique that is based on a focused electron beam and hence higher electron dose rate. In this paper, we report a simple and effective method to clean drop-cast TEM grids that contain NPs with ligands. Using a combination of activated carbon and ethanol, this method effectively reduces the amount of ligands on TEM grids, and therefore greatly improves the quality of electron microscopy images and subsequent analytical measurements. This ef cient and facile method can be helpful during electron microscopy investigation of different kinds of nanomaterials that suffer from ligand- induced contamination. |
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000612539600002 |
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0000-00-00 |
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0304-3991 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.843 |
Times cited |
10 |
Open Access |
OpenAccess |
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Notes |
This research was funded by the University Antwerp GOA project (ID 33928). DW acknowledges an Individual Fellowship funded by the Marie Sklodowska-Curie Actions (MSCA) in Horizon 2020 program (grant 894254 SuprAtom). |
Approved |
Most recent IF: 2.843 |
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Call Number |
EMAT @ emat @c:irua:174947 |
Serial |
6666 |
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Author |
Canossa, S.; Ferrari, E.; Sippel, P.; Fischer, J.K.H.; Pfattner, R.; Frison, R.; Masino, M.; Mas-Torrent, M.; Lunkenheimer, P.; Rovira, C.; Girlando, A. |
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Title |
Tetramethylbenzidine-TetrafluoroTCNQ (TMB-TCNQF(4)) : a narrow-gap semiconducting salt with room-temperature relaxor ferroelectric behavior |
Type |
A1 Journal article |
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Year |
2021 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
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Volume |
125 |
Issue |
46 |
Pages |
25816-25824 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
We present an extension and revision of the spectroscopic and structural data of the mixed-stack charge-transfer (CT) crystal 3,3 ',5,5 '-tetramethylbenzidine-tetrafluorotetracyano-quinodimethane (TMB-TCNQF4), associated with new electric and dielectric measurements. Refinement of synchrotron structural data at low temperature has led to revise the previously reported C2/m structure. The revised structure is P2(1)/m, with two dimerized stacks per unit cell, and is consistent with the low temperature vibrational data. However, polarized Raman data in the low-frequency region also indicate that by increasing temperature above 200 K, the structure presents an increasing degree of disorder, mainly along the stack axis. X-ray diffraction data at room temperature have confirmed that the correct structure is P2(1)/ m -no phase transitions -but did not allow substantiating the presence of disorder. On the other hand, dielectric measurements have evidenced a typical relaxor ferroelectric behavior already at room temperature, with a peak in the real part of dielectric constant epsilon'(T,v) around 200 K and 0.1 Hz. The relaxor behavior is explained in terms of the presence of spin solitons separating domains of opposite polarity that yield to ferroelectric nanodomains. TMB-TCNQF(4) is confirmed to be a narrow-gap band semiconductor (Ea similar to 0.3 eV) with a room-temperature conductivity of similar to 10(-4) Omega(-1) cm(-1). |
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000731170500008 |
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0000-00-00 |
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1932-7447; 1932-7455 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.536 |
Times cited |
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Not_Open_Access |
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Notes |
A.G. thanks Prof. Pascale Foury-Leylekian for very helpful discussions about the crystallographic issues. R.F. thanks Prof. Anthony Linden for his help in the X-ray diffraction data collection. J.K.H.F. and P.L. acknowledge funding from the Deutsche Forschungsgemeinschaft (DFG) via the Transregional Collaborative Research Center TRR80 (Augsburg, Munich). R.P. and M.M.-T. acknowledge support from the Marie Curie Cofund, Beatriu de Pinós Fellowships (Grant nos. AGAUR 2017 BP 00064). This work was also supported by the Spanish Ministry project GENESIS PID2019-111682RBI00, the “Severo Ochoa” Programme for Centers of Excellence in R&D (FUNFUTURE, CEX2019-000917-S), and the Generalitat de Catalunya (2017-SGR-918). The Elettra Synchrotron (CNR Trieste) is acknowledged for granting the beamtime at the single-crystal diffraction beamline XRD1 (Proposal ID 20185483). In Parma, the work has benefited from the equipment and support of the COMP-HUB Initiative, funded by the “Departments of Excellence” program of the |
Approved |
Most recent IF: 4.536 |
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Call Number |
UA @ admin @ c:irua:184866 |
Serial |
7066 |
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Author |
Velazco Torrejón, A. |
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Title |
Alternative scan strategies for high resolution STEM imaging |
Type |
Doctoral thesis |
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Year |
2021 |
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Abbreviated Journal |
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Pages |
131 p. |
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Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Currently, a large variety of materials are studied by transmission electron microscopy (TEM) as it offers the possibility to perform structural and elemental analysis at a local scale. Relatively recent advances in aberration correctors and electron sources allow the instrument to achieve atomic resolution. Along with these advances, a state-of-the-art technology has been reached in TEM. However, the instrument is far from being perfect and imperfections or external sources can make the interpretation of information troublesome. Environmental factors such as acoustic and mechanical vibrations, temperature fluctuations, etc., can induce sample drift and create image distortions. These distortions are enhanced in scanning operation because of the serial acquisition of the information, which are more apparent at atomic resolution as small field of views are imaged. In addition, scanning distortions are induced due to the finite time response of the scan coils. These types of distortions would reduce precision in atomic-scale strain analysis, for instance, in semiconductors. Most of the efforts to correct these distortions are focused on data processing techniques post-acquisition. Another limitation in TEM is beam damage effects. Beam damage arises because of the energy transferred to the sample in electron-sample interactions. In scanning TEM, at atomic resolution, the increased electron charge density (electron dose) carried on a sub-Å size electron probe may aggravate beam damage effects. Soft materials such as zeolites, organic, biological materials, etc., can be destroyed under irradiation limiting the amount of information that can be acquired. Current efforts to circumvent beam damage are mostly based on low electron dose acquisitions and data processing methods to maximize the signal at low dose conditions. In this thesis, a different approach is given to address drift and scanning distortions, as well as beam damage effects. Novel scan strategies are proposed for that purpose, which are shown to substantially overcome these issues compared to the standard scan method in TEM. |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:180973 |
Serial |
6852 |
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Skorikov, A.; Heyvaert, W.; Albrecht, W.; Pelt, D.M.; Bals, S. |
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Title |
EMAT Simulated 3D Nanoparticle Structures Dataset |
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Dataset |
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2021 |
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Dataset; Electron microscopy for materials research (EMAT) |
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This dataset contains 1000 simulated nanoparticle-like 3D structures and noisy EDX-like elemental maps based on them. These data are intended to be used for quantitative analysis of data processing methods in (EDX) tomography of nanoparticles and training the data-driven approaches for these tasks. The dataset is structured as follows: voxel_data/clean 3D voxel grid representation of the simulated nanoparticles. Voxel intensities are adjusted so that the total intensity equals 103. All 3D structures have unique identifiers in 0..999 range. The data derived from a 3D structure preserves this unique identifier. sinograms/clean Tilt series of projection images obtained from the corresponding 3D structures over an angular range of -75..75 degrees with a tilt step of 10 degrees to simulate a typical tilt series used in EDX tomography. Total intensity in each projection image equals 103. sinograms/noisy Tilt series of projection images corrupted with Poisson noise and an additional spatially uniform background noise. projections/clean Projection images extracted from the clean tilt series at 0 degrees tilt angle. projections/noisy Projection images extracted from the noisy tilt series at 0 degrees tilt angle. images/clean Visualizations of the clean projections as PNG images with the intensity range adjusted to 0..255 images/noisy Visualizations of the noisy projections as PNG images with the intensity range adjusted to 0..255 |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:180615 |
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6838 |
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Skorikov, A. |
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Fast approaches for investigating 3D elemental distribution in nanomaterials |
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Doctoral thesis |
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2021 |
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143 p. |
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Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Most recent IF: NA |
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UA @ admin @ c:irua:178855 |
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6795 |
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Roegiers, J. |
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Development of combined photocatalytic and active carbon fiber technology for indoor air purification based on Multiphysics models |
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Doctoral thesis |
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2021 |
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XXX, 197 p. |
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Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Sustainable Energy, Air and Water Technology (DuEL) |
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Exposure to volatile organic compounds (VOCs) remains a major public health concern. Indoor VOC concentrations typically far exceed outdoor levels due to a variety of emission sources and the stringent insulation measures that are imposed today. Many attempts have been made to use photocatalysis for indoor air purification. In an ideal situation, photocatalysis is capable of complete mineralization of VOCs to H2O and CO2, without any byproduct formation. Moreover, the process can take place at standard atmospheric conditions, i.e. ambient temperature and atmospheric pressure. However, successful exploitation is still impeded due to low conversion efficiency, significant pressure loss (and hence a high energy consumption) and byproduct formation. In the first part of this thesis an attempt was made to tackles these problems by designing a novel type of photocatalytic (PCO) reactor. The PCO device consists of a cylindrical vessel filled with TiO2-coated glass tubes and equipped with UV fluorescence lamps. It was investigated in terms of fluid dynamics, coating properties, UV-light distribution and photocatalytic activity. Experimental data was later used to develop and calibrate a Multiphysics model. The model proved to be a useful tool for designing and upscaling the PCO reactor. Consequently, an optimized prototype reactor was constructed and tested according the CEN-EN-16846-1 standard for VOC removal. Although the prototype showed promising results for lab-scale conditions, it struggled with byproduct formation when purifying ppb-level VOCs. In the second part of this thesis, activated carbon adsorption was investigated in order to combine it with photocatalysis. Activated carbon fiber was opted for its fast kinetics, high adsorption capacity and thermo-electrical regeneration. The filter was studied in detail regarding the adsorption of polar and apolar VOCs at indoor air concentration levels and regeneration capabilities. Experimental data was used to develop a Multiphysics model for activated carbon adsorption as well. Consequently, a novel type of ACF filter was developed using the Multiphysics model, which was equipped with electrodes in the tips of the pleats for effective thermal regeneration. In the last part, the combination of both ACF and PCO was studied using a realistic case study. Based on the Multiphysics model, the feasibility of a so-called hybrid air purification device could be investigated. The Multiphysics model shows promising results for this hybrid PCO-ACF system and hence, a demo setup was constructed for future research. |
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Most recent IF: NA |
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UA @ admin @ c:irua:181137 |
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6860 |
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Prabhakara, V. |
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Strain measurement for semiconductor applications with Raman spectroscopy and Transmission electron microscopy |
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Doctoral thesis |
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Year |
2021 |
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149 p. |
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Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Scaling down the size of transistors has been a trend for several decades which has led to improved transistor performance, increased transistor density and hence the overall computation power of IC chips. The trend slowed in recent years due to reliability and power consumption issues at the nanoscale. Hence strain is introduced into transistor channels that has beneficial effects on improving the mobility of charge carriers, providing an alternative pathway for enhancing transistor performance. Therefore, monitoring strain is vital for the semiconductor industry. With the recent trend of decreasing device dimensions (FinFETS ~ 10-20nm) and strain modulation being used throughout, industry needs a reliable and fast method as quality control or defect characterisation. Such a universal strain measurement method does not exist, and one relies on a combination of quantitative in-line methods and complex off-line approaches. In this thesis, I investigated TEM and Raman spectroscopy-based methodologies for strain measurement. In terms of TEM methodologies, advancements are made for the STEM moiré imaging, targeting strain spatial resolution enhancement. I introduce advanced quadrature demodulation and phase stepping interferometry applied to STEM moiré that greatly enhances the spatial resolution while providing enhanced field of view and sensitivity for strain measurement. We introduce ways to reduce scan distortions in strain maps using an alternative scan strategy called “Block scanning” and the non-linear regression applied for strain extraction. Prospects for 3D strain analysis using high-resolution tomography is also investigated which gives direct access for the full second order strain tensors calculation. Finally, we compare strain measurements from TEM techniques with inline techniques like Raman spectroscopy. Raman stress measurement involves sensitive identification of the TO and LO phonon peaks. Raman spectrum of strained Ge transistor channel consists of strongly overlapping peaks within the spectral resolution of the spectrometer. Hence, the process of deconvolution of the two peaks is rather challenging. Hence, we explore new polarisation geometries like radially polarised incoming light which was shown to ease the deconvolution problem resulting in improved precision for Raman stress–strain measurements. |
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Most recent IF: NA |
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UA @ admin @ c:irua:182261 |
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6847 |
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Pedrazo Tardajos, A. |
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Advanced graphene supports for 3D in situ transmission electron microscopy |
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Doctoral thesis |
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2021 |
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247 p. |
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Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Transmission electron microscopy (TEM) is an ideal tool to investigate nanomaterials. The information from TEM experiments allows us to link the structure and composition of nanomaterials to their intrinsic physical properties. However, despite the significant evolution of the TEM field during the last two decades, major progress is still possible through the development of optimal TEM techniques and supports. The results presented in this thesis focus on the optimization of sample supports and their application. Among the different options, graphene has previously been reported as useful sample support for electron microscopy due to its unparalleled properties, for example, it is the thinnest known support and provides a protective effect to the sample under investigation. Unfortunately, commercial graphene grids show poor quality, in terms of intactness and cleanness, inhibiting their wide application within the field. Therefore, this thesis focuses on the application of optimized graphene TEM grids, obtained by transferring high quality graphene using an advanced procedure. This improvement on the transfer has enabled the visualization of materials with low contrast and high sensitivity towards the electron beam, such as surface ligands capping gold nanoparticles or metal halide perovskites. Furthermore, the implemented protocol is not only of interest for conventional TEM grids but also a major benefit for in situ TEM studies, where the sample is investigated in real time under certain stimuli. Hence, the same graphene transfer technology can be also applied to advanced in situ MEMS holders dedicated for both heating and gas experiments, where the thickness and insulating nature of the silicon nitride (Si3N4) support may hamper some applications. By engineering periodic arrays of holes in their Si3N4 membrane by focused ion beam, onto which the graphene is transferred, it has been possible to get proof-of-concept 3D in situ investigations of heat-induced morphological and compositional transformations of complex nanosystems. As an example, it has enabled the investigation of the possible phase-transition of metal halide perovskites upon heating using 2D and 3D structural characterization. Moreover, it has allowed the study of in situ three-dimensional nanoparticle dynamics during gas phase catalysis as well as the first steps that would lead towards the design and creation of the first Graphene Gas Cell. Consequently, implementation of the advanced graphene transfer technology described in this thesis is envisaged to impact a broad range of future experiments. |
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Most recent IF: NA |
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UA @ admin @ c:irua:181143 |
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6836 |
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Jannis, D. |
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Novel detection schemes for transmission electron microscopy |
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Doctoral thesis |
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2021 |
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iv, 208 p. |
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Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Electron microscopy is an excellent tool which provides resolution down to the atomic scale with up to pm precision in locating atoms. The characterization of materials in these length scales is of utmost importance to answer questions in biology, chemistry and material science. The successful implementation of aberration-corrected microscopes made atomic resolution imaging relatively easy, this could give the impression that the development of novel electron microscopy techniques would stagnate and only the application of these instruments as giant magnifying tools would continue. This is of course not true and a multitude of problems still exist in electron microscopy. Two of such issues are discussed below. One of the biggest problems in electron microscopy is the presence of beam damage which occurs due the fact that the highly energetic incoming electrons have sufficient kinetic energy to change the structure of the material. The amount of damage induced depends on the dose, hence minimizing this dose during an experiment is beneficial. This minimizing of the total dose comes at the expense of more noise due to the counting nature of the electrons. For this reason, the implementation of four dimensional scanning transmission electron microscopy (4D STEM) experiments has reduced the total dose needed per acquisition. However, the current cameras used to measure the diffraction patterns are still two orders of magnitude slower than to the conventional STEM methods. Improving the acquisition speed would make the 4D STEM technique more feasible and is of utmost importance for the beam sensitive materials since less dose is used during the acquisition. In TEM there is not only the possibility to perform imaging experiments but also spectroscopic measurements. There are two frequently used methods: electron energy-loss spectroscopy (EELS) and energy dispersive x-ray spectroscopy (EDX). EELS measures the energy-loss spectrum of the incoming electron which gives information on the available excitations in the material providing elemental sensitivity. In EDX, the characteristic x-rays, arising from the decay of an atom which is initially excited due to the incoming electrons, are detected providing similar elemental analysis. Both methods are able to provide comparable elemental information where in certain circumstances one outperforms the other. However, both methods have a detection limit of approximately 100-1000 ppm which is not sufficient for some materials. In this thesis, two novel techniques which can make significant progress for the two problems discussed above. |
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Most recent IF: NA |
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UA @ admin @ c:irua:182404 |
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6872 |
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Du, K. |
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Title |
In situ TEM study on the manipulation of ferroelectrics |
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Doctoral thesis |
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2021 |
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91 p. |
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Doctoral thesis; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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The strong correlated oxide systems attract a lot of attentions of scientists recently, the coexistence and interplay between various degrees of freedom, such as charge, spin and orbital, has been demonstrated to induce some fancy physical properties and phenomenon, including metal-insulator transition, high temperature superconductivity, colossal magnetoresistance. As a part of the strong correlated oxide systems, the ferroelectrics is abundant in both physical properties and application. First, if the electric dipole continuously rotating around a stable core then a topological structure is produced. If people could manipulate the topological structure and simultaneously observe the structure evolution, with external field applied on the topological structure, then it is very likely for such kind of ferroelectrics to be the next generation of storage, for it is reported to need low power input and produce high density of storage. In the other hand, in solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, such as ferroelectricity and ferromagnetism, antiferroelectricity and antiferromagnetism, but ferrielectricity and ferrimagnetism kept telling a disparate story in microscopic level. The claimed “ferrielectrics” in existing research is equivalent to ferroelectric ones, thus the findings of such a real irreducible solids would complete the last piece of the ferroelectrics family. While solving the above two questions remain challengeable: the size of topological structure is small (typically below 10 nm), general characterization methods are insufficient for such high demand on space resolution, not to mention manipulating and observing its dynamic behavior at an atomic level. Here, employing the spherical aberration corrected electron microscope, we applied external field (heating and bias) on ferroelectrics. Combined with high-end characterization methods including the high-angle annular dark field (HAADF-STEM) image, Electron Energy Loss Spectroscopy (EELS) and integrated differential phase contrast (iDPC), the dynamic evolution of ferroelectrics are observed and analyzed. The main findings of this paper could be concluded as listed here: (1) PbTiO3(001)// SrTiO3(001) is grown on DyScO3 and SrRuO3 by pusled laser deposition, the atomical EDS mapping results reveal that the interface between PTO and STO is atomically sharp. Increasing the thickness of PTO from 1 uc to 21 uc, the topological structure wihtin PTO layer would transform from a/c domain to wave, vortex and finally flux closure domain. The geometric phase analysis results (GPA) reveal that above topological structures are corresponding to various strain. (2) Combined with in-situ biasing holder, the electric bias was applied on polar vortex, and it evolved from vortex (0 V) to polar wave (2 V) and finally polar down (5 V). EELS analysis was performed and we find that negative charge is gathered at vortex core, which turns the Ti4+ to Ti3+ there. The oxygen vacancy at negative polarization surface and the negative charge at the positive polarization surface realized the polarization screening of polar down domain. (3) Through the atomic inspection and analysis on lattice structure of BaFe2Se3, the near ladders within single unit are found to be different in degree of tetramerization, thus leading to a residual polarization along the a-axis. The further in-situ heating and biasing experiment was conducted on BaFe2Se3, and the strong and weak ladders are proved to be independent for their behavior under external field. This findings distinguishes ferrielectrics from ferroelectrics in solids. |
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Most recent IF: NA |
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UA @ admin @ c:irua:179310 |
Serial |
6842 |
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Author |
De wael, A. |
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Title |
Model-based quantitative scanning transmission electron microscopy for measuring dynamic structural changes at the atomic scale |
Type |
Doctoral thesis |
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Year |
2021 |
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Pages |
xiv, 146 p. |
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Doctoral thesis; Electron microscopy for materials research (EMAT) |
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Abstract |
Nanomaterialen kunnen uiterst interessante eigenschappen vertonen voor een verscheidenheid aan veelbelovende toepassingen, gaande van zonnecrème tot batterijen voor elektrische auto’s. Een nanometer is een miljard keer kleiner dan een meter. Op deze schaal kunnen de materiaaleigenschappen volledig verschillen van bulkmaterialen op grotere schaal. Bovendien hangen de eigenschappen van nanomaterialen sterk af van hun exacte grootte en vorm. Kleine verschillen in de posities van de atomen, in de grootte-orde van een picometer (nog eens duizend maal kleiner dan een nanometer), kunnen de fysische eigenschappen al drastisch beïnvloeden. Daarom is een betrouwbare kwantificering van de atomaire structuur van kritisch belang om de evolutie naar materiaalontwerp mogelijk te maken en inzicht te verwerven in de relatie tussen de fysische eigenschappen en de structuur van nanomaterialen. Daarnaast kan de atomaire structuur van nanomaterialen ook veranderen in de loop van de tijd ten gevolge van verschillende fysische processen. Het onderzoek dat in deze thesis gepresenteerd wordt, maakt het mogelijk om de dynamische structuurveranderingen van nanomaterialen betrouwbaar te kwantificeren op atomaire schaal door gebruik te maken van raster transmissie elektronenmicroscopie (STEM). Ik heb dit gerealiseerd door methodes te ontwikkelen waarmee ik het aantal atomen “achter elkaar” kan tellen in elke atoomkolom van een nanomateriaal, en dit op basis van beelden opgenomen met een elektronenmicroscoop. Een belangrijk verschil met telmethodes voor de analyse van een enkel beeld is het schatten van de kans dat een atoomkolom atomen zal verliezen of bijkrijgen van het ene naar het andere beeld in de tijdreeks. Deze kwantitatieve methode kan het ontrafelen van de tijdsafhankelijke structuur-eigenschappen relatie van een nanomateriaal mogelijk maken, wat uiteindelijk kan leiden tot efficiënter design en productie van nanomaterialen voor innovatieve toepassingen. |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:179514 |
Serial |
6870 |
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Milovanović, S.P.; Andelkovic, M.; Covaci, L.; Peeters, F.M. |
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Title |
Band flattening in buckled monolayer graphene |
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A1 Journal article |
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Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
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Volume |
102 |
Issue |
24 |
Pages |
245427 |
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A1 Journal article; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
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The strain fields of periodically buckled graphene induce a periodic pseudomagnetic field (PMF) that modifies the electronic band structure. From the geometry, amplitude, and period of the periodic pseudomagnetic field, we determine the necessary conditions to access the regime of correlated phases by examining the band flattening. As compared to twisted bilayer graphene the proposed system has the advantages that (1) only a single layer of graphene is needed, (2) one is not limited to hexagonal superlattices, and (3) narrower flat bandwidth and larger separation between flat bands can be induced. We, therefore, propose that periodically strained graphene single layers can become a platform for the exploration of exotic many-body phases. |
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000602844600007 |
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2020-12-28 |
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2469-9969; 2469-9950 |
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UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
11 |
Open Access |
OpenAccess |
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Notes |
; S.P.M. is supported by the Flemish Science Foundation (FWO). We thank E. Y. Andrei, Y. Jiang, and J. Mao for fruitful discussions. ; |
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:175021 |
Serial |
6684 |
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Imran, M.; Ramade, J.; Di Stasio, F.; De Franco, M.; Buha, J.; Van Aert, S.; Goldoni, L.; Lauciello, S.; Prato, M.; Infante, I.; Bals, S.; Manna, L. |
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Title |
Alloy CsCdxPb1–xBr3Perovskite Nanocrystals: The Role of Surface Passivation in Preserving Composition and Blue Emission |
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A1 Journal article |
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Year |
2020 |
Publication |
Chemistry Of Materials |
Abbreviated Journal |
Chem Mater |
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32 |
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Pages |
acs.chemmater.0c03825 |
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A1 Journal article; Electron microscopy for materials research (EMAT) |
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Various strategies have been proposed to engineer the band gap of metal halide perovskite nanocrystals (NCs) while preserving their structure and composition and thus ensuring spectral stability of the emission color. An aspect that has only been marginally investigated is how the type of surface passivation influences the structural/color stability of AMX3 perovskite NCs composed of two different M2+ cations. Here, we report the synthesis of blue-emitting Cs-oleate capped CsCdxPb1–xBr3 NCs, which exhibit a cubic perovskite phase containing Cd-rich domains of Ruddlesden–Popper phases (RP phases). The RP domains spontaneously transform into pure orthorhombic perovskite ones upon NC aging, and the emission color of the NCs shifts from blue to green over days. On the other hand, postsynthesis ligand exchange with various Cs-carboxylate or ammonium bromide salts, right after NC synthesis, provides monocrystalline NCs with cubic phase, highlighting the metastability of RP domains. When NCs are treated with Cs-carboxylates (including Cs-oleate), most of the Cd2+ ions are expelled from NCs upon aging, and the NCs phase evolves from cubic to orthorhombic and their emission color changes from blue to green. Instead, when NCs are coated with ammonium bromides, the loss of Cd2+ ions is suppressed and the NCs tend to retain their blue emission (both in colloidal dispersions and in electroluminescent devices), as well as their cubic phase, over time. The improved compositional and structural stability in the latter cases is ascribed to the saturation of surface vacancies, which may act as channels for the expulsion of Cd2+ ions from NCs. |
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000603288800034 |
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2020-12-04 |
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0897-4756 |
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UA library record; WoS full record; WoS citing articles |
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Impact Factor |
8.6 |
Times cited |
44 |
Open Access |
OpenAccess |
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Notes |
European Commission; Fonds Wetenschappelijk Onderzoek, G.0267.18N ; H2020 European Research Council, 770887 815128 851794 ; We acknowledge funding from the FLAG-ERA JTC2019 project PeroGas. S.B., and S.V.A. acknowledges funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC Consolidator Grants #815128REALNANO and #770887PICOMETRICS) and from the Research Foundation Flanders (FWO, Belgium) through project funding G.0267.18N. F.D.S. acknowledges the funding from ERC starting grant NANOLED (851794). The computational work was carried out on the Dutch National e-infrastructure with the support of the SURF Cooperative; sygma |
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Most recent IF: 8.6; 2020 IF: 9.466 |
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Call Number |
EMAT @ emat @c:irua:174004 |
Serial |
6659 |
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Ding, L.; Jidkova, S.; Greuter, M.J.W.; Van Herck, K.; Goossens, M.; Martens, P.; de Bock, G.H.; Van Hal, G. |
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Coverage determinants of breast cancer screening in Flanders : an evaluation of the past decade |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
International journal for equity in health |
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19 |
Issue |
1 |
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212 |
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A1 Journal article; Electron microscopy for materials research (EMAT); Social Epidemiology & Health Policy (SEHPO) |
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Background Breast cancer (BC) is the most common cancer in women in the developed world. In order to find developing cancers in an early stage, BC screening is commonly used. In Flanders, screening is performed in and outside an organized breast cancer screening program (BCSP). However, the determinants of BC screening coverage for both screening strategies are yet unknown. Objective To assess the determinants of BC screening coverage in Flanders. Methods Reimbursement data were used to attribute a screening status to each woman in the target population for the years 2008-2016. Yearly coverage data were categorized as screening inside or outside BCSP or no screening. Data were clustered by municipality level. A generalized linear equation model was used to assess the determinants of screening type. Results Over all years and municipalities, the median screening coverage rate inside and outside BCSP was 48.40% (IQR: 41.50-54.40%) and 14.10% (IQR: 9.80-19.80%) respectively. A higher coverage rate outside BSCP was statistically significantly (P < 0.001) associated with more crowded households (OR: 3.797, 95% CI: 3.199-4.508), younger age, higher population densities (OR: 2.528, 95% CI: 2.455-2.606), a lower proportion of unemployed job seekers (OR: 0.641, 95% CI: 0.624-0.658) and lower use of dental care (OR: 0.969, 95% CI: 0.967-0.972). Conclusion Coverage rate of BC screening is not optimal in Flanders. Women with low SES that are characterized by younger age, living in a high population density area, living in crowded households, or having low dental care are less likely to be screened for BC in Flanders. If screened, they are more likely to be screened outside the BCSP. |
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000595753100002 |
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2020-11-27 |
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OpenAccess |
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Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:174374 |
Serial |
6721 |
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Albrecht, W.; Bals, S. |
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Fast Electron Tomography for Nanomaterials |
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A1 Journal article |
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2020 |
Publication |
Journal Of Physical Chemistry C |
Abbreviated Journal |
J Phys Chem C |
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acs.jpcc.0c08939 |
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A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Electron tomography (ET) has become a well-established technique to visualize nanomaterials in three dimensions. A vast richness in information can be gained by ET, but the conventional acquisition of a tomography series is an inherently slow process on the order of 1 h. The slow acquisition limits the applicability of ET for monitoring dynamic processes or visualizing nanoparticles, which are sensitive to the electron beam. In this Perspective, we summarize recent work on the development of emerging experimental and computational schemes to enhance the data acquisition process. We particularly focus on the application of these fast ET techniques for beam-sensitive materials and highlight insight into dynamic transformations of nanoparticles under external stimuli, which could be gained by fast in situ ET. Moreover, we discuss challenges and possible solutions for simultaneously increasing the speed and quality of fast ET. |
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000608876900003 |
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2020-11-27 |
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1932-7447 |
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UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
26 |
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OpenAccess |
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Notes |
H2020 Research Infrastructures, 823717 ; H2020 European Research Council, 815128 ; The authors acknowledge funding from the European Research Council under the European Union’s Horizon 2020 research and innovation program (ERC Consolidator Grant No. 815128-REALNANO) and the European Commission (EUSMI). The authors furthermore acknowledge funding from the European Union’s Horizon 2020 research and innovation program, ESTEEM3. The authors also acknowledge contributions from all co-workers that have contributed over the years: J. Batenburg and co-workers, A. Béché, E. Bladt, L. Liz-Marzán and co-workers, H. Pérez Garza and co-workers, A. Skorikov, S. Skrabalak and co-workers, S. Van Aert, A. van Blaaderen and co-workers, H. Vanrompay, and J. Verbeeck.; sygma |
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Most recent IF: 3.7; 2020 IF: 4.536 |
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EMAT @ emat @c:irua:173965 |
Serial |
6656 |
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Lin, S.-C.; Kuo, C.-T.; Shao, Y.-C.; Chuang, Y.-D.; Geessinck, J.; Huijben, M.; Rueff, J.-P.; Graff, I.L.; Conti, G.; Peng, Y.; Bostwick, A.; Gullikson, E.; Nemsak, S.; Vailionis, A.; Gauquelin, N.; Verbeeck, J.; Ghiringhelli, G.; Schneider, C.M.; Fadley, C.S. |
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Two-dimensional electron systems in perovskite oxide heterostructures : role of the polarity-induced substitutional defects |
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A1 Journal article |
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2020 |
Publication |
Physical review materials |
Abbreviated Journal |
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4 |
Issue |
11 |
Pages |
115002 |
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A1 Journal article; Electron microscopy for materials research (EMAT) |
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The discovery of a two-dimensional electron system (2DES) at the interfaces of perovskite oxides such as LaAlO3 and SrTiO3 has motivated enormous efforts in engineering interfacial functionalities with this type of oxide heterostructures. However, the fundamental origins of the 2DES are still not understood, e.g., the microscopic mechanisms of coexisting interface conductivity and magnetism. Here we report a comprehensive spectroscopic investigation on the depth profile of 2DES-relevant Ti 3d interface carriers using depthand element-specific techniques like standing-wave excited photoemission and resonant inelastic scattering. We found that one type of Ti 3d interface carriers, which give rise to the 2DES are located within three unit cells from the n-type interface in the SrTiO3 layer. Unexpectedly, another type of interface carriers, which are polarity-induced Ti-on-Al antisite defects, reside in the first three unit cells of the opposing LaAlO3 layer (similar to 10 angstrom). Our findings provide a microscopic picture of how the localized and mobile Ti 3d interface carriers distribute across the interface and suggest that the 2DES and 2D magnetism at the LaAlO3/SrTiO3 interface have disparate explanations as originating from different types of interface carriers. |
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000592432200004 |
Publication Date |
2020-11-20 |
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2475-9953 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.4 |
Times cited |
7 |
Open Access |
OpenAccess |
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Notes |
; We thank G. M. De Luca and L. Braicovich for discussions. Charles S. Fadley was deceased on August 1, 2019. We are grateful for his significant contributions to this work. We thank Advanced Light Source for the access to Beamline 8.0.3 (qRIXS) via Proposal No. 09892 and beamline 7.0.2 (MAESTRO) via Proposal No. RA-00291 that contributed to the results presented here. We thank synchrotron SOLEIL (via Proposal No. 99180118) for the access to Beamline GALAXIES. This work was supported by the U.S. Department of Energy (DOE) under Contract No. DE-AC02-05CH11231 (Advanced Light Source), and by DOE Contract No. DE-SC0014697 through the University of California, Davis (S.-C.L., C.-T.K, and C.S.F.), and from the Julich Research Center, Peter Grunberg Institute, PGI-6. I. L. G. wishes to thank Brazilian scientific agencies CNPQ (Project No. 200789/2017-1) and CAPES (CAPES-PrInt-UFPR) for their financial support. J.V. and N.G. acknowledge funding from the Geconcentreerde Onderzoekacties (GOA) project “Solarpaint” of the University of Antwerp and the European Union's horizon 2020 research and innovation program ES-TEEM3 under grant agreement no 823717. The Qu-Ant-EM microscope used in this study was partly funded by the Hercules fund from the Flemish Government. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 3.4; 2020 IF: NA |
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Call Number |
UA @ admin @ c:irua:174316 |
Serial |
6713 |
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Author |
Savchenko, T.M.; Buzzi, M.; Howald, L.; Ruta, S.; Vijayakumar, J.; Timm, M.; Bracher, D.; Saha, S.; Derlet, P.M.; Béché, A.; Verbeeck, J.; Chantrell, R.W.; Vaz, C.A.F.; Nolting, F.; Kleibert, A. |
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| |
Title |
Single femtosecond laser pulse excitation of individual cobalt nanoparticles |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Physical Review B |
Abbreviated Journal |
Phys Rev B |
|
| |
Volume |
102 |
Issue |
20 |
Pages |
205418 |
|
| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
Laser-induced manipulation of magnetism at the nanoscale is a rapidly growing research topic with potential for applications in spintronics. In this work, we address the role of the scattering cross section, thermal effects, and laser fluence on the magnetic, structural, and chemical stability of individual magnetic nanoparticles excited by single femtosecond laser pulses. We find that the energy transfer from the fs laser pulse to the nanoparticles is limited by the Rayleigh scattering cross section, which in combination with the light absorption of the supporting substrate and protective layers determines the increase in the nanoparticle temperature. We investigate individual Co nanoparticles (8 to 20 nm in size) as a prototypical model system, using x-ray photoemission electron microscopy and scanning electron microscopy upon excitation with single femtosecond laser pulses of varying intensity and polarization. In agreement with calculations, we find no deterministic or stochastic reversal of the magnetization in the nanoparticles up to intensities where ultrafast demagnetization or all-optical switching is typically reported in thin films. Instead, at higher fluences, the laser pulse excitation leads to photo-chemical reactions of the nanoparticles with the protective layer, which results in an irreversible change in the magnetic properties. Based on our findings, we discuss the conditions required for achieving laser-induced switching in isolated nanomagnets. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000589602000005 |
Publication Date |
2020-11-16 |
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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 |
2469-9950 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
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| |
Impact Factor |
3.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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| |
Notes |
This work received funding by the Swiss National Foundation (SNF) (Grants No. 200021160186 and No. 2002153540), the Swiss Nanoscience Institute (SNI) (Grant No. SNI P1502), the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 737093 (FEMTOTERABYTE), and the COST Action CA17123 (MAGNETOFON). Part of this work was performed at the SIM beamline of the Swiss Light Source (SLS), Paul Scherrer Institut, Villigen, Switzerland. Part of the simulations were undertaken on the VIKING cluster, which is a high-performance compute facility provided by the University of York. We kindly acknowledge Anja Weber from PSI for preparation of substrates with marker structures. A.B. and Jo Verbeeck acknowledge funding through FWO Project No. G093417N (“Compressed sensing enabling low dose imaging in transmission electron microscopy”) from the Flanders Research Fund. Jo Verbeeck acknowledges funding from the European Union’s Horizon 2020 research and innovation program under Grant Agreement No. 823717 – ESTEEM3. S.S. acknowledges ETH Zurich Post-Doctoral fellowship and Marie Curie actions for people COFUND program.; esteem3JRA; esteem3reported |
Approved |
Most recent IF: 3.7; 2020 IF: 3.836 |
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| |
Call Number |
EMAT @ emat @c:irua:174273 |
Serial |
6669 |
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| Permanent link to this record |
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| |
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Author |
Chen, B.; Gauquelin, N.; Jannis, D.; Cunha, D.M.; Halisdemir, U.; Piamonteze, C.; Lee, J.H.; Belhadi, J.; Eltes, F.; Abel, S.; Jovanovic, Z.; Spreitzer, M.; Fompeyrine, J.; Verbeeck, J.; Bibes, M.; Huijben, M.; Rijnders, G.; Koster, G. |
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| |
Title |
Strain-engineered metal-to-insulator transition and orbital polarization in nickelate superlattices integrated on silicon |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Advanced Materials |
Abbreviated Journal |
Adv Mater |
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| |
Volume |
|
Issue |
|
Pages |
2004995 |
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| |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
Epitaxial growth of SrTiO3 (STO) on silicon greatly accelerates the monolithic integration of multifunctional oxides into the mainstream semiconductor electronics. However, oxide superlattices (SLs), the birthplace of many exciting discoveries, remain largely unexplored on silicon. In this work, LaNiO3/LaFeO3 SLs are synthesized on STO-buffered silicon (Si/STO) and STO single-crystal substrates, and their electronic properties are compared using dc transport and X-ray absorption spectroscopy. Both sets of SLs show a similar thickness-driven metal-to-insulator transition, albeit with resistivity and transition temperature modified by the different amounts of strain. In particular, the large tensile strain promotes a pronounced Ni 3dx2-y2 orbital polarization for the SL grown on Si/STO, comparable to that reported for LaNiO3 SL epitaxially strained to DyScO3 substrate. Those results illustrate the ability to integrate oxide SLs on silicon with structure and property approaching their counterparts grown on STO single crystal, and also open up new prospects of strain engineering in functional oxides based on the Si platform. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000588146500001 |
Publication Date |
2020-11-11 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
0935-9648 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
29.4 |
Times cited |
18 |
Open Access |
OpenAccess |
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| |
Notes |
; This work is supported by the international M-ERA.NET project SIOX (project 4288) and H2020 project ULPEC (project 732642). M.S. acknowledges funding from Slovenian Research Agency (Grants No. J2-9237 and No. P2-0091). This work received support from the ERC CoG MINT (#615759) and from a PHC Van Gogh grant. M.B. thanks the French Academy of Science and the Royal Netherlands Academy of Arts and Sciences for supporting his stays in the Netherlands. This project has received funding as a transnational access project from the European Union's Horizon 2020 research and innovation programme under grant agreement No 823717 – ESTEEM3. N.G. and J.V. acknowledge GOA project “Solarpaint” of the University of Antwerp. ; esteem3TA; esteem3reported |
Approved |
Most recent IF: 29.4; 2020 IF: 19.791 |
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| |
Call Number |
UA @ admin @ c:irua:173516 |
Serial |
6617 |
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| Permanent link to this record |
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Author |
Kamminga, M.E.; Batuk, M.; Hadermann, J.; Clarke, S.J. |
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Title |
Misfit phase (BiSe)1.10NbSe2 as the origin of superconductivity in niobium-doped bismuth selenide |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Communications Materials |
Abbreviated Journal |
Commun Mater |
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| |
Volume |
1 |
Issue |
1 |
Pages |
82 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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| |
Abstract |
Topological superconductivity is of great contemporary interest and has been proposed in doped Bi<sub>2</sub>Se<sub>3</sub>, in which electron-donating atoms such as Cu, Sr or Nb have been intercalated into the Bi<sub>2</sub>Se<sub>3</sub>structure. For Nb<sub><italic>x</italic></sub>Bi<sub>2</sub>Se<sub>3</sub>, with<italic>T</italic><sub>c</sub> ~ 3 K, it is assumed in the literature that Nb is inserted in the van der Waals gap. However, in this work an alternative origin for the superconductivity in Nb-doped Bi<sub>2</sub>Se<sub>3</sub>is established. In contrast to previous reports, it is deduced that Nb intercalation in Bi<sub>2</sub>Se<sub>3</sub>does not take place. Instead, the superconducting behaviour in samples of nominal composition Nb<sub><italic>x</italic></sub>Bi<sub>2</sub>Se<sub>3</sub>results from the (BiSe)<sub>1.10</sub>NbSe<sub>2</sub>misfit phase that is present in the sample as an impurity phase for small<italic>x</italic>(0.01 ≤ <italic>x</italic> ≤ 0.10) and as a main phase for large<italic>x</italic>(<italic>x</italic> = 0.50). The structure of this misfit phase is studied in detail using a combination of X-ray diffraction and transmission electron microscopy techniques. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000610580800001 |
Publication Date |
2020-11-10 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
2662-4443 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
Times cited |
|
Open Access |
OpenAccess |
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Notes |
M.E.K. was supported by the Netherlands Organisation for Scientific Research (NWO, grant code 019.181EN.003). We also acknowledge support from the EPSRC (EP/ R042594/1, EP/P018874/1, EP/M020517/1) and the Leverhulme Trust (RPG-2018-377). J.H. acknowledges support from the University of Antwerp through BOF Grant No. 31445. We thank DLS Ltd for beam time (EE18786), Dr Clare Murray for assistance on I11 and Dr Jon Wade from the Department of Earth Sciences, University of Oxford for performing the SEM measurements. We also thank Dr Michal Dušak and Dr Václav Petřiček for their advice concerning the use of the Jana2006 software. |
Approved |
Most recent IF: NA |
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| |
Call Number |
EMAT @ emat @c:irua:176116 |
Serial |
6705 |
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| Permanent link to this record |
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Author |
Zhang, Z.; Bourgeois, L.; Zhang, Y.; Rosalie, J.M.; Medhekar, N. |
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Title |
Advanced imaging and simulations of precipitate interfaces in aluminium alloys and their role in phase transformations |
Type |
P1 Proceeding |
| |
Year |
2020 |
Publication |
MATEC web of conferences
T2 – 17th International Conference on Aluminium Alloys (ICAA), October 26-29, 2020 |
Abbreviated Journal |
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Volume |
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Issue |
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Pages |
09003 |
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Keywords |
P1 Proceeding; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Precipitation is accompanied by the formation and migration of heterophase interfaces. Using the combined approach of advanced imaging and atomistic simulations, we studied the precipitate-matrix interfaces in various aluminium alloy systems, aiming to resolve their detailed atomic structures and illuminate their role in phase transformations. |
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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 |
000652552200053 |
Publication Date |
2020-11-05 |
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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 |
326 |
Series Issue |
|
Edition |
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| |
ISSN |
2261-236x; 2274-7214 |
ISBN |
|
Additional Links |
UA library record; WoS full record |
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Impact Factor |
|
Times cited |
|
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ admin @ c:irua:179147 |
Serial |
6851 |
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| Permanent link to this record |
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Author |
Irtem, E.; Arenas Esteban, D.; Duarte, M.; Choukroun, D.; Lee, S.; Ibáñez, M.; Bals, S.; Breugelmans, T. |
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Title |
Ligand-Mode Directed Selectivity in Cu–Ag Core–Shell Based Gas Diffusion Electrodes for CO2Electroreduction |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Acs Catalysis |
Abbreviated Journal |
Acs Catal |
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Volume |
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Issue |
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Pages |
13468-13478 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Applied Electrochemistry & Catalysis (ELCAT) |
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Abstract |
Bimetallic nanoparticles with tailored size and specific composition have shown promise as stable and selective catalysts for electrochemical reduction of CO2 (CO2R) in batch systems. Yet, limited effort was devoted to understand the effect of ligand coverage and postsynthesis treatments on CO2 reduction, especially under industrially applicable conditions, such as at high currents (>100 mA/cm2) using gas diffusion electrodes (GDE) and flow reactors. In this work, Cu–Ag core–shell nanoparticles (11 ± 2 nm) were prepared with three different surface modes: (i) capped with oleylamine, (ii) capped with monoisopropylamine, and (iii) surfactant free with a reducing borohydride agent; Cu–Ag (OAm), Cu–Ag (MIPA), and Cu–Ag (NaBH4), respectively. The ligand exchange and removal was evidenced by infrared spectroscopy (ATR-FTIR) analysis, whereas high-resolution scanning transmission electron microscopy (HAADF-STEM) showed their effect on the interparticle distance and nanoparticle rearrangement. Later on, we developed a process-on-substrate method to track these effects on CO2R. Cu–Ag (OAm) gave a lower on-set potential for hydrocarbon production, whereas Cu–Ag (MIPA) and Cu–Ag (NaBH4) promoted syngas production. The electrochemical impedance and surface area analysis on the well-controlled electrodes showed gradual increases in the electrical conductivity and active surface area after each surface treatment. We found that the increasing amount of the triple phase boundaries (the meeting point for the electron–electrolyte–CO2 reactant) affect the required electrode potential and eventually the C+2e̅/C2e̅ product ratio. This study highlights the importance of the electron transfer to those active sites affected by the capping agents—particularly on larger substrates that are crucial for their industrial application. |
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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 |
000592978900031 |
Publication Date |
2020-11-04 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2155-5435 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.9 |
Times cited |
23 |
Open Access |
OpenAccess |
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Notes |
The authors also acknowledge financial support from the University Research Fund (BOF-GOA-PS ID No. 33928). S.L. has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie SkłodowskaCurie Grant Agreement No. 665385. |
Approved |
Most recent IF: 12.9; 2020 IF: 10.614 |
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Call Number |
EMAT @ emat @c:irua:173803 |
Serial |
6432 |
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| Permanent link to this record |
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Author |
Xu, X.; Jones, M.A.; Cassidy, S.J.; Manuel, P.; Orlandi, F.; Batuk, M.; Hadermann, J.; Clarke, S.J. |
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Title |
Magnetic Ordering in the Layered Cr(II) Oxide Arsenides Sr2CrO2Cr2As2and Ba2CrO2Cr2As2 |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Inorganic Chemistry |
Abbreviated Journal |
Inorg Chem |
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| |
Volume |
59 |
Issue |
21 |
Pages |
15898-15912 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Sr2CrO2Cr2As2 and Ba2CrO2Cr2As2 with Cr2+ ions in CrO2 sheets and in CrAs layers crystallize with the Sr2Mn3Sb2O2 structure (space group I4/mmm, Z = 2) and lattice parameters a = 4.00800(2) Å, c = 18.8214(1) Å (Sr2CrO2Cr2As2) and a = 4.05506(2) Å, c = 20.5637(1) Å (Ba2CrO2Cr2As2) at room temperature. Powder neutron diffraction reveals checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the arsenide layers below TN1Sr, of 600(10) K (Sr2CrO2Cr2As2) and TN1Ba 465(5) K (Ba2CrO2Cr2As2) with the moments initially directed perpendicular to the layers in both compounds. Checkerboard-type antiferromagnetic ordering of the Cr2+ ions in the oxide layer below 230(5) K for Ba2CrO2Cr2As2 occurs with these moments also perpendicular to the layers, consistent with the orientation preferences of d4 moments in the two layers. In contrast, below 330(5) K in Sr2CrO2Cr2As2, the oxide layer Cr2+ moments are initially oriented in the CrO2 plane; but on further cooling, these moments rotate to become perpendicular to the CrO2 planes, while the moments in the arsenide layers rotate by 90° with the moments on the two sublattices remaining orthogonal throughout [behavior recently reported independently by Liu et al. [Liu et al. Phys. Rev. B 2018, 98, 134416]]. In Sr2CrO2Cr2As2, electron diffraction and high resolution powder X-ray diffraction data show no evidence for a structural distortion that would allow the two Cr2+ sublattices to couple, but high resolution neutron powder diffraction data suggest a small incommensurability between the magnetic structure and the crystal structure, which may account for the coupling of the two sublattices and the observed spin reorientation. The saturation values of the Cr2+ moments in the CrO2 layers (3.34(1) μB (for Sr2CrO2Cr2As2) and 3.30(1) μB (for Ba2CrO2Cr2As2)) are larger than those in the CrAs layers (2.68(1) μB for Sr2CrO2Cr2As2 and 2.298(8) μB for Ba2CrO2Cr2As2) reflecting greater covalency in the arsenide layers. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000588738100035 |
Publication Date |
2020-11-02 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0020-1669 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4.6 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
We thank the UK EPSRC (EP/M020517/1 and EP/P018874/ 1) and the Leverhulme Trust (RPG-2014-221) for funding and the ISIS pulsed neutron and muon source (RB1610357 and RB1700075) and the Diamond Light Source Ltd. (EE13284 and EE18786) for the award of beam time. We thank Dr. A. Baker and Dr. C. Murray for support on I11. |
Approved |
Most recent IF: 4.6; 2020 IF: 4.857 |
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Call Number |
EMAT @ emat @c:irua:176058 |
Serial |
6704 |
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Author |
Frolov, A.S.; Sanchez-Barriga, J.; Callaert, C.; Hadermann, J.; Fedorov, A., V; Usachov, D.Y.; Chaika, A.N.; Walls, B.C.; Zhussupbekov, K.; Shvets, I., V.; Muntwiler, M.; Amati, M.; Gregoratti, L.; Varykhalov, A.Y.; Rader, O.; Yashina, L., V. |
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Title |
Atomic and electronic structure of a multidomain GeTe crystal |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Acs Nano |
Abbreviated Journal |
Acs Nano |
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Volume |
14 |
Issue |
12 |
Pages |
16576-16589 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Renewed interest in the ferroelectric semi-conductor germanium telluride was recently triggered by the direct observation of a giant Rashba effect and a 30-year-old dream about a functional spin field-effect transistor. In this respect, all-electrical control of the spin texture in this material in combination with ferroelectric properties at the nanoscale would create advanced functionalities in spintronics and data information processing. Here, we investigate the atomic and electronic properties of GeTe bulk single crystals and their (111) surfaces. We succeeded in growing crystals possessing solely inversion domains of similar to 10 nm thickness parallel to each other. Using HAADF-TEM we observe two types of domain boundaries, one of them being similar in structure to the van der Waals gap in layered materials. This structure is responsible for the formation of surface domains with preferential Te-termination (similar to 68%) as we determined using photoelectron diffraction and XPS. The lateral dimensions of the surface domains are in the range of similar to 10-100 nm, and both Ge- and Te-terminations reveal no reconstruction. Using spin-ARPES we establish an intrinsic quantitative relationship between the spin polarization of pure bulk states and the relative contribution of different terminations, a result that is consistent with a reversal of the spin texture of the bulk Rashba bands for opposite configurations of the ferroelectric polarization within individual nanodomains. Our findings are important for potential applications of ferroelectric Rashba semiconductors in nonvolatile spintronic devices with advanced memory and computing capabilities at the nanoscale. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000603308800022 |
Publication Date |
2020-11-02 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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| |
ISSN |
1936-0851 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
17.1 |
Times cited |
|
Open Access |
OpenAccess |
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Notes |
|
Approved |
Most recent IF: 17.1; 2020 IF: 13.942 |
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Call Number |
UA @ admin @ c:irua:175027 |
Serial |
6716 |
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Author |
Busatto, S.; Ruiter, M. de; Jastrzebski, J.T.B.H.; Albrecht, W.; Pinchetti, V.; Brovelli, S.; Bals, S.; Moret, M.-E.; de Mello Donega, C. |
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Title |
Luminescent Colloidal InSb Quantum Dots from In Situ Generated Single-Source Precursor |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Acs Nano |
Abbreviated Journal |
Acs Nano |
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| |
Volume |
14 |
Issue |
10 |
Pages |
13146-13160 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Despite recent advances, the synthesis of colloidal InSb quantum dots (QDs) remains underdeveloped, mostly due to the lack of suitable precursors. In this work, we use Lewis acid–base interactions between Sb(III) and In(III) species formed at room temperature in situ from commercially available compounds (viz., InCl3, Sb[NMe2]3 and a primary alkylamine) to obtain InSb adduct complexes. These complexes are successfully used as precursors for the synthesis of colloidal InSb QDs ranging from 2.8 to 18.2 nm in diameter by fast coreduction at sufficiently high temperatures (≥230 °C). Our findings allow us to propose a formation mechanism for the QDs synthesized in our work, which is based on a nonclassical nucleation event, followed by aggregative growth. This yields ensembles with multimodal size distributions, which can be fractionated in subensembles with relatively narrow polydispersity by postsynthetic size fractionation. InSb QDs with diameters below 7.0 nm have the zinc blende crystal structure, while ensembles of larger QDs (≥10 nm) consist of a mixture of wurtzite and zinc blende QDs. The QDs exhibit photoluminescence with small Stokes shifts and short radiative lifetimes, implying that the emission is due to band-edge recombination and that the direct nature of the bandgap of bulk InSb is preserved in InSb QDs. Finally, we constructed a sizing curve correlating the peak position of the lowest energy absorption transition with the QD diameters, which shows that the band gap of colloidal InSb QDs increases with size reduction following a 1/d dependence. |
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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 |
000586793400068 |
Publication Date |
2020-10-27 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
|
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| |
ISSN |
1936-0851 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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| |
Impact Factor |
17.1 |
Times cited |
21 |
Open Access |
OpenAccess |
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Notes |
S.B. and C.d.M.D. acknowledge financial support from the division of Chemical Sciences (CW) of The Netherlands Organization for Scientific Research (NWO) under Grant No. TOP.715.016.001. W.A. acknowledges an Individual Fellowship from the Marie Sklodowska-Curie actions (MSCA) under the EU?s Horizon 2020 program (Grant No. 797153, SOPMEN). This project has received funding from the European Commission Grant (EUSMI E180900184) and European Research Council (ERC Consolidator Grant No. 815128 REALNANO).; sygma |
Approved |
Most recent IF: 17.1; 2020 IF: 13.942 |
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Call Number |
EMAT @ emat @c:irua:173862 |
Serial |
6438 |
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| Permanent link to this record |
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Author |
Lebedev, N.; Stehno, M.; Rana, A.; Gauquelin, N.; Verbeeck, J.; Brinkman, A.; Aarts, J. |
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Title |
Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO₃/SrTiO₃ interfaces |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Journal Of Physics-Condensed Matter |
Abbreviated Journal |
J Phys-Condens Mat |
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| |
Volume |
33 |
Issue |
5 |
Pages |
055001 |
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| |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We have studied the transport properties of LaTiO3/SrTiO3 (LTO/STO) heterostructures. In spite of 2D growth observed in reflection high energy electron diffraction, transmission electron microscopy images revealed that the samples tend to amorphize. Still, we observe that the structures are conducting, and some of them exhibit high conductance and/or superconductivity. We established that conductivity arises mainly on the STO side of the interface, and shows all the signs of the two-dimensional electron gas usually observed at interfaces between STO and LTO or LaAlO3, including the presence of two electron bands and tunability with a gate voltage. Analysis of magnetoresistance (MR) and superconductivity indicates the presence of spatial fluctuations of the electronic properties in our samples. That can explain the observed quasilinear out-of-plane MR, as well as various features of the in-plane MR and the observed superconductivity. |
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Corporate Author |
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Place of Publication |
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Wos |
000588209300001 |
Publication Date |
2020-10-14 |
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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 |
0953-8984 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.7 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
; NL and JA gratefully acknowledge the financial support of the research program DESCO, which is financed by the Netherlands Organisation for Scientific Research (NWO). The authors thank J Jobst, S Smink, K Lahabi and G Koster for useful discussion. ; |
Approved |
Most recent IF: 2.7; 2020 IF: 2.649 |
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Call Number |
UA @ admin @ c:irua:173679 |
Serial |
6545 |
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| Permanent link to this record |
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Author |
Canossa, S.; Wuttke, S. |
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Title |
Functionalization chemistry of porous materials |
Type |
Editorial |
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Year |
2020 |
Publication |
Advanced Functional Materials |
Abbreviated Journal |
Adv Funct Mater |
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Volume |
30 |
Issue |
41 |
Pages |
2003875 |
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| |
Keywords |
Editorial; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000580514700004 |
Publication Date |
2020-10-08 |
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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 |
1616-301x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
19 |
Times cited |
1 |
Open Access |
OpenAccess |
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Notes |
; ; |
Approved |
Most recent IF: 19; 2020 IF: 12.124 |
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Call Number |
UA @ admin @ c:irua:173614 |
Serial |
6524 |
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Author |
De wael, A.; De Backer, A.; Van Aert, S. |
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Title |
Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations |
Type |
A1 Journal article |
| |
Year |
2020 |
Publication |
Ultramicroscopy |
Abbreviated Journal |
Ultramicroscopy |
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Volume |
219 |
Issue |
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Pages |
113131 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We present a quantitative method which allows us to reliably measure dynamic changes in the atomic structure of monatomic crystalline nanomaterials from a time series of atomic resolution annular dark field scanning transmission electron microscopy images. The approach is based on the so-called hidden Markov model and estimates the number of atoms in each atomic column of the nanomaterial in each frame of the time series. We discuss the origin of the improved performance for time series atom-counting as compared to the current state-of-the-art atom-counting procedures, and show that the so-called transition probabilities that describe the probability for an atomic column to lose or gain one or more atoms from frame to frame are particularly important. Using these transition probabilities, we show that the method can also be used to estimate the probability and cross section related to structural changes. Furthermore, we explore the possibilities for applying the method to time series recorded under variable environmental conditions. The method is shown to be promising for a reliable quantitative analysis of dynamic processes such as surface diffusion, adatom dynamics, beam effects, or in situ experiments. |
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Corporate Author |
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Place of Publication |
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Editor |
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Wos |
000594770500003 |
Publication Date |
2020-10-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0304-3991 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.2 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 770887 and No. 823717 ESTEEM3). The authors acknowledge financial support from the Research Foundation Flanders (FWO, Belgium) through grants to A.D.w. and A.D.B. and projects G.0502.18N and EOS 30489208. |
Approved |
Most recent IF: 2.2; 2020 IF: 2.843 |
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Call Number |
EMAT @ emat @c:irua:172449 |
Serial |
6417 |
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Author |
Wang, J.; Gauquelin, N.; Huijben, M.; Verbeeck, J.; Rijnders, G.; Koster, G. |
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Title |
Metal-insulator transition of SrVO 3 ultrathin films embedded in SrVO 3 / SrTiO 3 superlattices |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl Phys Lett |
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Volume |
117 |
Issue |
13 |
Pages |
133105 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The metal-insulator transition (MIT) in strongly correlated oxides is a topic of great interest for its potential applications, such as Mott field effect transistors and sensors. We report that the MIT in high quality epitaxial SrVO3 (SVO) thin films is present as the film thickness is reduced, lowering the dimensionality of the system, and electron-electron correlations start to become the dominant interactions. The critical thickness of 3 u.c is achieved by avoiding effects due to off-stoichiometry using optimal growth conditions and excluding any surface effects by a STO capping layer. Compared to the single SVO thin films, conductivity enhancement in SVO/STO superlattices is observed. This can be explained by the interlayer coupling effect between SVO sublayers in the superlattices. Magnetoresistance and Hall measurements indicate that the dominant driving force of MIT is the electron–electron interaction. |
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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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Wos |
000577126100001 |
Publication Date |
2020-09-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-6951 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
4 |
Times cited |
8 |
Open Access |
OpenAccess |
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Notes |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek, 13HTSM01 ; |
Approved |
Most recent IF: 4; 2020 IF: 3.411 |
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Call Number |
EMAT @ emat @c:irua:172461 |
Serial |
6415 |
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Author |
Pourbabak, S.; Orekhov, A.; Schryvers, D. |
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Title |
Twin-jet electropolishing for damage-free transmission electron microscopy specimen preparation of metallic microwires |
Type |
A1 Journal article |
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Year |
2020 |
Publication |
Microscopy Research And Technique |
Abbreviated Journal |
Microsc Res Techniq |
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Volume |
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Issue |
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Pages |
1-7 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
A method to prepare TEM specimens from metallic microwires and based on conventional twin-jet electropolishing is introduced. The wire is embedded in an opaque epoxy resin medium and the hardened resin is mechanically polished to reveal the wire on both sides. The resin containing wire is then cut into discs of the appropriate size. The obtained embedded wire is electropolished in a conventional twin-jet electropolishing machine until electron transparency in large areas without radiation damage is achieved. |
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Corporate Author |
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Publisher |
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Place of Publication |
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Language |
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Wos |
000567944200001 |
Publication Date |
2020-09-28 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1059-910x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.5 |
Times cited |
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Open Access |
OpenAccess |
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Notes |
; Fonds Wetenschappelijk Onderzoek, Grant/Award Number: G.0366.15N ; |
Approved |
Most recent IF: 2.5; 2020 IF: 1.147 |
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Call Number |
UA @ admin @ c:irua:171969 |
Serial |
6642 |
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| Permanent link to this record |
