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Cioni M, Delle Piane M, Polino D, Rapetti D, Crippa M, Irmak EA, Van Aert S, Bals S, Pavan GM. Sampling Real-Time Atomic Dynamics in Metal Nanoparticles by Combining Experiments, Simulations, and Machine Learning. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307261. [PMID: 38654692 PMCID: PMC11220678 DOI: 10.1002/advs.202307261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/23/2024] [Indexed: 04/26/2024]
Abstract
Even at low temperatures, metal nanoparticles (NPs) possess atomic dynamics that are key for their properties but challenging to elucidate. Recent experimental advances allow obtaining atomic-resolution snapshots of the NPs in realistic regimes, but data acquisition limitations hinder the experimental reconstruction of the atomic dynamics present within them. Molecular simulations have the advantage that these allow directly tracking the motion of atoms over time. However, these typically start from ideal/perfect NP structures and, suffering from sampling limits, provide results that are often dependent on the initial/putative structure and remain purely indicative. Here, by combining state-of-the-art experimental and computational approaches, how it is possible to tackle the limitations of both approaches and resolve the atomistic dynamics present in metal NPs in realistic conditions is demonstrated. Annular dark-field scanning transmission electron microscopy enables the acquisition of ten high-resolution images of an Au NP at intervals of 0.6 s. These are used to reconstruct atomistic 3D models of the real NP used to run ten independent molecular dynamics simulations. Machine learning analyses of the simulation trajectories allow resolving the real-time atomic dynamics present within the NP. This provides a robust combined experimental/computational approach to characterize the structural dynamics of metal NPs in realistic conditions.
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Affiliation(s)
- Matteo Cioni
- Department of Applied Science and TechnologyPolitecnico di TorinoCorso Duca degli Abruzzi 24Torino10129Italy
| | - Massimo Delle Piane
- Department of Applied Science and TechnologyPolitecnico di TorinoCorso Duca degli Abruzzi 24Torino10129Italy
| | - Daniela Polino
- Department of Innovative TechnologiesUniversity of Applied Sciences and Arts of Southern SwitzerlandPolo Universitario LuganoCampus Est, Via la Santa 1Lugano‐Viganello6962Switzerland
| | - Daniele Rapetti
- Department of Applied Science and TechnologyPolitecnico di TorinoCorso Duca degli Abruzzi 24Torino10129Italy
| | - Martina Crippa
- Department of Applied Science and TechnologyPolitecnico di TorinoCorso Duca degli Abruzzi 24Torino10129Italy
| | - Ece Arslan Irmak
- EMAT and NANOlab Center of ExcellenceUniversity of AntwerpGroenenborgerlaan 171Antwerp2020Belgium
| | - Sandra Van Aert
- EMAT and NANOlab Center of ExcellenceUniversity of AntwerpGroenenborgerlaan 171Antwerp2020Belgium
| | - Sara Bals
- EMAT and NANOlab Center of ExcellenceUniversity of AntwerpGroenenborgerlaan 171Antwerp2020Belgium
| | - Giovanni M. Pavan
- Department of Applied Science and TechnologyPolitecnico di TorinoCorso Duca degli Abruzzi 24Torino10129Italy
- Department of Innovative TechnologiesUniversity of Applied Sciences and Arts of Southern SwitzerlandPolo Universitario LuganoCampus Est, Via la Santa 1Lugano‐Viganello6962Switzerland
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2
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Liu W, Yu J, Li T, Li S, Ding B, Guo X, Cao A, Sha Q, Zhou D, Kuang Y, Sun X. Self-protecting CoFeAl-layered double hydroxides enable stable and efficient brine oxidation at 2 A cm -2. Nat Commun 2024; 15:4712. [PMID: 38830888 PMCID: PMC11148009 DOI: 10.1038/s41467-024-49195-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/27/2024] [Indexed: 06/05/2024] Open
Abstract
Low-energy consumption seawater electrolysis at high current density is an effective way for hydrogen production, however the continuous feeding of seawater may result in the accumulation of Cl-, leading to severe anode poisoning and corrosion, thereby compromising the activity and stability. Herein, CoFeAl layered double hydroxide anodes with excellent oxygen evolution reaction activity are synthesized and delivered stable catalytic performance for 350 hours at 2 A cm-2 in the presence of 6-fold concentrated seawater. Comprehensive analysis reveals that the Al3+ ions in electrode are etched off by OH- during oxygen evolution reaction process, resulting in M3+ vacancies that boost oxygen evolution reaction activity. Additionally, the self-originated Al(OH)n- is found to adsorb on the anode surface to improve stability. An electrode assembly based on a micropore membrane and CoFeAl layered double hydroxide electrodes operates continuously for 500 hours at 1 A cm-2, demonstrating their feasibility in brine electrolysis.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Jiage Yu
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Tianshui Li
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Shihang Li
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Boyu Ding
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Xinlong Guo
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Aiqing Cao
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Qihao Sha
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Daojin Zhou
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China.
| | - Yun Kuang
- Ocean Hydrogen Energy R&D Center, Research Institute of Tsinghua University in Shenzhen, Shenzhen, 518057, China.
| | - Xiaoming Sun
- State Key Laboratory of Chemical Resource Engineering, College of Chemistry, Beijing University of Chemical Technology, Beijing, 100029, China.
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3
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Şentürk DG, De Backer A, Van Aert S. Element specific atom counting for heterogeneous nanostructures: Combining multiple ADF STEM images for simultaneous thickness and composition determination. Ultramicroscopy 2024; 259:113941. [PMID: 38387236 DOI: 10.1016/j.ultramic.2024.113941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 02/24/2024]
Abstract
In this paper, a methodology is presented to count the number of atoms in heterogeneous nanoparticles based on the combination of multiple annular dark field scanning transmission electron microscopy (ADF STEM) images. The different non-overlapping annular detector collection regions are selected based on the principles of optimal statistical experiment design for the atom-counting problem. To count the number of atoms, the total intensities of scattered electrons for each atomic column, the so-called scattering cross-sections, are simultaneously compared with simulated library values for the different detector regions by minimising the squared differences. The performance of the method is evaluated for simulated Ni@Pt and Au@Ag core-shell nanoparticles. Our approach turns out to be a dose efficient alternative for the investigation of beam-sensitive heterogeneous materials as compared to the combination of ADF STEM and energy dispersive X-ray spectroscopy.
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Affiliation(s)
- D G Şentürk
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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4
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Liu S, Dong J, Ma Z, Hu W, Deng Y, Shi Y, Wang X, Qiu Y, Walther T. The evolution of indium precipitation in gallium focused ion beam prepared samples of InGaAs/InAlAs quantum wells under electron beam irradiation. J Microsc 2024; 293:169-176. [PMID: 38112123 DOI: 10.1111/jmi.13251] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 11/20/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023]
Abstract
Gallium ion (Ga+ ) beam damage induced indium (In) precipitation in indium gallium arsenide (InGaAs)/indium aluminium arsenide (InAlAs) multiple quantum wells and its corresponding evolution under electron beam irradiation was investigated by valence electron energy loss spectroscopy (VEELS) and high-angle annular dark-field imaging (HAADF) in scanning transmission electron microscopy (STEM). Compared with argon ion milling for sample preparation, the heavier projectiles of Ga+ ions pose a risk to trigger In formation in the form of tiny metallic In clusters. These are shown to be sensitive to electron irradiation and can increase in number and size under the electron beam, deteriorating the structure. Our finding reveals the potential risk of formation of In clusters during focused ion beam (FIB) preparation of InGaAs/InAlAs quantum well samples and their subsequent growth under STEM-HAADF imaging, where initially invisible In clusters of a few atoms can move and swell during electron beam exposure.
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Affiliation(s)
- Shuo Liu
- College of Electronic and Information, Southwest Minzu University, State Ethnic Affairs Commission, Chengdu, China
| | - Jiawei Dong
- College of Electronic and Information, Southwest Minzu University, State Ethnic Affairs Commission, Chengdu, China
| | - Zhenyu Ma
- College of Electronic and Information, Southwest Minzu University, State Ethnic Affairs Commission, Chengdu, China
| | - Wenyu Hu
- Pico Center, SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Yong Deng
- College of Electronic and Information, Southwest Minzu University, State Ethnic Affairs Commission, Chengdu, China
- Pico Center, SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Yuechun Shi
- Photon Technology Research Center, Yongjiang Laboratory, Ningbo, China
| | - Xiaoyi Wang
- College of Electronic and Information, Southwest Minzu University, State Ethnic Affairs Commission, Chengdu, China
| | - Yang Qiu
- Pico Center, SUSTech Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Thomas Walther
- Department Electronic & Electrical Engineering, University of Sheffield, Sheffield, UK
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5
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Şentürk DG, Yu CP, De Backer A, Van Aert S. Atom counting from a combination of two ADF STEM images. Ultramicroscopy 2024; 255:113859. [PMID: 37778104 DOI: 10.1016/j.ultramic.2023.113859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/13/2023] [Accepted: 09/21/2023] [Indexed: 10/03/2023]
Abstract
To understand the structure-property relationship of nanostructures, reliably quantifying parameters, such as the number of atoms along the projection direction, is important. Advanced statistical methodologies have made it possible to count the number of atoms for monotype crystalline nanoparticles from a single ADF STEM image. Recent developments enable one to simultaneously acquire multiple ADF STEM images. Here, we present an extended statistics-based method for atom counting from a combination of multiple statistically independent ADF STEM images reconstructed from non-overlapping annular detector collection regions which improves the accuracy and allows one to retrieve precise atom-counts, especially for images acquired with low electron doses and multiple element structures.
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Affiliation(s)
- D G Şentürk
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - C P Yu
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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6
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Eliasson H, Niu Y, Palmer RE, Grönbeck H, Erni R. Support-facet-dependent morphology of small Pt particles on ceria. NANOSCALE 2023; 15:19091-19098. [PMID: 37929917 DOI: 10.1039/d3nr04701f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Direct atomic scale information on how the structure of supported nanoparticles is affected by the metal-support interaction is rare. Using scanning transmission electron microscopy, we provide direct evidence of a facet-dependent support interaction for Pt nanoparticles on CeO2, governing the dimensionality of small platinum particles. Our findings indicate that particles consisting of less than ∼130 atoms prefer a 3D shape on CeO2(111) facets, while 2D raft structures are favored on CeO2(100) facets. Measurements of stationary particles on both surface facets are supplemented by time resolved measurements following a single particle with atomic resolution as it migrates from CeO2(111) to CeO2(100), undergoing a dimensionality change from 3D to 2D. The intricate transformation mechanism reveals how the 3D particle disassembles and completely wets a neighboring CeO2(100) facet. Density functional theory calculations confirm the structure-trend and reveal the thermodynamic driving force for the migration of small particles. Knowledge of the presented metal-support interactions is crucial to establish structure-function relationships in a range of applications based on supported nanostructures.
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Affiliation(s)
- Henrik Eliasson
- Electron Microscopy Center, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
| | - Yubiao Niu
- Nanomaterials Lab, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK
| | - Richard E Palmer
- Nanomaterials Lab, Faculty of Science and Engineering, Swansea University, Bay Campus, Swansea, SA1 8EN, UK
| | - Henrik Grönbeck
- Department of Physics and Competence Centre for Catalysis, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Rolf Erni
- Electron Microscopy Center, Empa - Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
- Department of Materials, ETH Zurich, CH-8093 Zurich, Switzerland
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7
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Krause FF, Rosenauer A. Atom counting based on Voronoi averaged STEM intensities using a crosstalk correction scheme. Ultramicroscopy 2023; 256:113867. [PMID: 37871357 DOI: 10.1016/j.ultramic.2023.113867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 10/25/2023]
Abstract
If quantitative scanning transmission electron microscopy is used for very precise thickness measurements with atomic resolution, it is commonly referred to as »atom counting«. Due to scattering and the finite probe extent the signal recorded in one atomic column is dependent not only on its own height but also on the height of its neighbours. Especially for thicker specimens this crosstalk effect can have significant impact on the measured intensity. If it is not appropriately accounted for in the evaluation, it can result in a deterioration of accuracy that impedes the possibility of actual atom counting. However, as the number of possible neighbour configurations can be excessively large, a comprehensive consideration of all in the evaluation reference is neigh impossible. This work proposes a method that allows for the a-posteriori reduction of crosstalk during the evaluation by algebraic means. Based on a parametric model, which is described in detail in the article, the crosstalk is expressed by an invertible matrix. Applying the inverted matrix to the measurement yields crosstalk corrected intensity values with very little computational effort. These can subsequently be evaluated by direct comparison to simple reference data. The working principle of the method is presented on the example of crystalline gold. The crosstalk parametrisation is found by fitting a model to sets of specifically created multislice simulations. The parameters are given for both aberration corrected and uncorrected STEM. Subsequently the abilities and potential of the technique are assessed in simulative studies on multiple model systems including gold nanoparticles. Overall a significant and robust improvement of the attainable precision can be demonstrated making the proposed method a promising tool for reference-based atom counting.
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Affiliation(s)
- Florian F Krause
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany.
| | - Andreas Rosenauer
- Institut für Festkörperphysik, Universität Bremen, Otto-Hahn-Allee 1, 28359 Bremen, Germany; MAPEX Center for Materials and Processes, Universität Bremen, Bibliotheksstraße 1, 28359 Bremen, Germany
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8
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Lobato I, De Backer A, Van Aert S. Real-time simulations of ADF STEM probe position-integrated scattering cross-sections for single element fcc crystals in zone axis orientation using a densely connected neural network. Ultramicroscopy 2023; 251:113769. [PMID: 37279607 DOI: 10.1016/j.ultramic.2023.113769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 05/08/2023] [Accepted: 05/26/2023] [Indexed: 06/08/2023]
Abstract
Quantification of annular dark field (ADF) scanning transmission electron microscopy (STEM) images in terms of composition or thickness often relies on probe-position integrated scattering cross sections (PPISCS). In order to compare experimental PPISCS with theoretically predicted ones, expensive simulations are needed for a given specimen, zone axis orientation, and a variety of microscope settings. The computation time of such simulations can be in the order of hours using a single GPU card. ADF STEM simulations can be efficiently parallelized using multiple GPUs, as the calculation of each pixel is independent of other pixels. However, most research groups do not have the necessary hardware, and, in the best-case scenario, the simulation time will only be reduced proportionally to the number of GPUs used. In this manuscript, we use a learning approach and present a densely connected neural network that is able to perform real-time ADF STEM PPISCS predictions as a function of atomic column thickness for most common face-centered cubic (fcc) crystals (i.e., Al, Cu, Pd, Ag, Pt, Au and Pb) along [100] and [111] zone axis orientations, root-mean-square displacements, and microscope parameters. The proposed architecture is parameter efficient and yields accurate predictions for the PPISCS values for a wide range of input parameters that are commonly used for aberration-corrected transmission electron microscopes.
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Affiliation(s)
- I Lobato
- EMAT, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | - A De Backer
- EMAT, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - S Van Aert
- EMAT, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Department of Physics, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
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9
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Monai M, Jenkinson K, Melcherts AEM, Louwen JN, Irmak EA, Van Aert S, Altantzis T, Vogt C, van der Stam W, Duchoň T, Šmíd B, Groeneveld E, Berben P, Bals S, Weckhuysen BM. Restructuring of titanium oxide overlayers over nickel nanoparticles during catalysis. Science 2023; 380:644-651. [PMID: 37167405 DOI: 10.1126/science.adf6984] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Reducible supports can affect the performance of metal catalysts by the formation of suboxide overlayers upon reduction, a process referred to as the strong metal-support interaction (SMSI). A combination of operando electron microscopy and vibrational spectroscopy revealed that thin TiOx overlayers formed on nickel/titanium dioxide catalysts during 400°C reduction were completely removed under carbon dioxide hydrogenation conditions. Conversely, after 600°C reduction, exposure to carbon dioxide hydrogenation reaction conditions led to only partial reexposure of nickel, forming interfacial sites in contact with TiOx and favoring carbon-carbon coupling by providing a carbon species reservoir. Our findings challenge the conventional understanding of SMSIs and call for more-detailed operando investigations of nanocatalysts at the single-particle level to revisit static models of structure-activity relationships.
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Affiliation(s)
- Matteo Monai
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, Netherlands
| | - Kellie Jenkinson
- EMAT and NANOlab Center of Excellence, University of Antwerp, 2020 Antwerp, Belgium
| | - Angela E M Melcherts
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, Netherlands
| | - Jaap N Louwen
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, Netherlands
| | - Ece A Irmak
- EMAT and NANOlab Center of Excellence, University of Antwerp, 2020 Antwerp, Belgium
| | - Sandra Van Aert
- EMAT and NANOlab Center of Excellence, University of Antwerp, 2020 Antwerp, Belgium
| | | | - Charlotte Vogt
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, Netherlands
| | - Ward van der Stam
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, Netherlands
| | - Tomáš Duchoň
- Peter-Grünberg-Institut 6, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Břetislav Šmíd
- Department of Surface and Plasma Science, Faculty of Mathematics and Physics, Charles University, 180 00 Prague, Czech Republic
| | | | - Peter Berben
- BASF Nederland B.V., 3454 PK De Meern, Netherlands
| | - Sara Bals
- EMAT and NANOlab Center of Excellence, University of Antwerp, 2020 Antwerp, Belgium
| | - Bert M Weckhuysen
- Inorganic Chemistry and Catalysis Group, Institute for Sustainable and Circular Chemistry and Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, Netherlands
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10
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De Backer A, Bals S, Van Aert S. A decade of atom-counting in STEM: From the first results toward reliable 3D atomic models from a single projection. Ultramicroscopy 2023; 247:113702. [PMID: 36796120 DOI: 10.1016/j.ultramic.2023.113702] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/03/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023]
Abstract
Quantitative structure determination is needed in order to study and understand nanomaterials at the atomic scale. Materials characterisation resulting in precise structural information is a crucial point to understand the structure-property relation of materials. Counting the number of atoms and retrieving the 3D atomic structure of nanoparticles plays an important role here. In this paper, an overview will be given of the atom-counting methodology and its applications over the past decade. The procedure to count the number of atoms will be discussed in detail and it will be shown how the performance of the method can be further improved. Furthermore, advances toward mixed element nanostructures, 3D atomic modelling based on the atom-counting results, and quantifying the nanoparticle dynamics will be highlighted.
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Affiliation(s)
- A De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Bals
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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11
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Zhang Z, Lobato I, De Backer A, Van Aert S, Nellist P. Fast generation of calculated ADF-EDX scattering cross-sections under channelling conditions. Ultramicroscopy 2023; 246:113671. [PMID: 36621195 DOI: 10.1016/j.ultramic.2022.113671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 12/21/2022] [Accepted: 12/26/2022] [Indexed: 12/29/2022]
Abstract
Advanced materials often consist of multiple elements which are arranged in a complicated structure. Quantitative scanning transmission electron microscopy is useful to determine the composition and thickness of nanostructures at the atomic scale. However, significant difficulties remain to quantify mixed columns by comparing the resulting atomic resolution images and spectroscopy data with multislice simulations where dynamic scattering needs to be taken into account. The combination of the computationally intensive nature of these simulations and the enormous amount of possible mixed column configurations for a given composition indeed severely hamper the quantification process. To overcome these challenges, we here report the development of an incoherent non-linear method for the fast prediction of ADF-EDX scattering cross-sections of mixed columns under channelling conditions. We first explain the origin of the ADF and EDX incoherence from scattering physics suggesting a linear dependence between those two signals in the case of a high-angle ADF detector. Taking EDX as a perfect incoherent reference mode, we quantitatively examine the ADF longitudinal incoherence under different microscope conditions using multislice simulations. Based on incoherent imaging, the atomic lensing model previously developed for ADF is now expanded to EDX, which yields ADF-EDX scattering cross-section predictions in good agreement with multislice simulations for mixed columns in a core-shell nanoparticle and a high entropy alloy. The fast and accurate prediction of ADF-EDX scattering cross-sections opens up new opportunities to explore the wide range of ordering possibilities of heterogeneous materials with multiple elements.
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Affiliation(s)
- Zezhong Zhang
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, United Kingdom.
| | - Ivan Lobato
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Annick De Backer
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sandra Van Aert
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | - Peter Nellist
- Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, United Kingdom.
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12
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Botifoll M, Pinto-Huguet I, Arbiol J. Machine learning in electron microscopy for advanced nanocharacterization: current developments, available tools and future outlook. NANOSCALE HORIZONS 2022; 7:1427-1477. [PMID: 36239693 DOI: 10.1039/d2nh00377e] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In the last few years, electron microscopy has experienced a new methodological paradigm aimed to fix the bottlenecks and overcome the challenges of its analytical workflow. Machine learning and artificial intelligence are answering this call providing powerful resources towards automation, exploration, and development. In this review, we evaluate the state-of-the-art of machine learning applied to electron microscopy (and obliquely, to materials and nano-sciences). We start from the traditional imaging techniques to reach the newest higher-dimensionality ones, also covering the recent advances in spectroscopy and tomography. Additionally, the present review provides a practical guide for microscopists, and in general for material scientists, but not necessarily advanced machine learning practitioners, to straightforwardly apply the offered set of tools to their own research. To conclude, we explore the state-of-the-art of other disciplines with a broader experience in applying artificial intelligence methods to their research (e.g., high-energy physics, astronomy, Earth sciences, and even robotics, videogames, or marketing and finances), in order to narrow down the incoming future of electron microscopy, its challenges and outlook.
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Affiliation(s)
- Marc Botifoll
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
| | - Ivan Pinto-Huguet
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193 Barcelona, Catalonia, Spain.
- ICREA, Pg. Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
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13
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De Backer A, Zhang Z, van den Bos KHW, Bladt E, Sánchez-Iglesias A, Liz-Marzán LM, Nellist PD, Bals S, Van Aert S. Element Specific Atom Counting at the Atomic Scale by Combining High Angle Annular Dark Field Scanning Transmission Electron Microscopy and Energy Dispersive X-ray Spectroscopy. SMALL METHODS 2022; 6:e2200875. [PMID: 36180399 DOI: 10.1002/smtd.202200875] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/29/2022] [Indexed: 06/16/2023]
Abstract
A new methodology is presented to count the number of atoms in multimetallic nanocrystals by combining energy dispersive X-ray spectroscopy (EDX) and high angle annular dark field scanning transmission electron microscopy (HAADF STEM). For this purpose, the existence of a linear relationship between the incoherent HAADF STEM and EDX images is exploited. Next to the number of atoms for each element in the atomic columns, the method also allows quantification of the error in the obtained number of atoms, which is of importance given the noisy nature of the acquired EDX signals. Using experimental images of an Au@Ag core-shell nanorod, it is demonstrated that 3D structural information can be extracted at the atomic scale. Furthermore, simulated data of an Au@Pt core-shell nanorod show the prospect to characterize heterogeneous nanostructures with adjacent atomic numbers.
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Affiliation(s)
- Annick De Backer
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Zezhong Zhang
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Karel H W van den Bos
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Eva Bladt
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Ana Sánchez-Iglesias
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014, Donostia-San Sebastián, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 20014, Donostia-San Sebastián, Spain
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014, Donostia-San Sebastián, Spain
- Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 20014, Donostia-San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48009, Bilbao, Spain
| | - Peter D Nellist
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
| | - Sara Bals
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
| | - Sandra Van Aert
- EMAT, University of Antwerp, 2020, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, 2020, Antwerp, Belgium
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14
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De Wael A, De Backer A, Yu CP, Sentürk DG, Lobato I, Faes C, Van Aert S. Three Approaches for Representing the Statistical Uncertainty on Atom-Counting Results in Quantitative ADF STEM. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 29:1-9. [PMID: 36117265 DOI: 10.1017/s1431927622012284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
A decade ago, a statistics-based method was introduced to count the number of atoms from annular dark-field scanning transmission electron microscopy (ADF STEM) images. In the past years, this method was successfully applied to nanocrystals of arbitrary shape, size, and composition (and its high accuracy and precision has been demonstrated). However, the counting results obtained from this statistical framework are so far presented without a visualization of the actual uncertainty about this estimate. In this paper, we present three approaches that can be used to represent counting results together with their statistical error, and discuss which approach is most suited for further use based on simulations and an experimental ADF STEM image.
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Affiliation(s)
- Annelies De Wael
- EMAT, University of Antwerp, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium
| | - Annick De Backer
- EMAT, University of Antwerp, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium
| | - Chu-Ping Yu
- EMAT, University of Antwerp, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium
| | - Duygu Gizem Sentürk
- EMAT, University of Antwerp, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium
| | - Ivan Lobato
- EMAT, University of Antwerp, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium
| | - Christel Faes
- I-BioStat, Data Science Institute, Hasselt University, Hasselt, Belgium
| | - Sandra Van Aert
- EMAT, University of Antwerp, Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium
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15
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Optimal experiment design for element specific atom counting using multiple annular dark field scanning transmission electron microscopy detectors. Ultramicroscopy 2022; 242:113626. [DOI: 10.1016/j.ultramic.2022.113626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 09/22/2022] [Accepted: 09/24/2022] [Indexed: 11/19/2022]
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16
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Schwenker E, Kolluru VSC, Guo J, Zhang R, Hu X, Li Q, Paul JT, Hersam MC, Dravid VP, Klie R, Guest JR, Chan MKY. Ingrained: An Automated Framework for Fusing Atomic-Scale Image Simulations into Experiments. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2102960. [PMID: 35384282 DOI: 10.1002/smll.202102960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/20/2021] [Indexed: 06/14/2023]
Abstract
To fully leverage the power of image simulation to corroborate and explain patterns and structures in atomic resolution microscopy, an initial correspondence between the simulation and experimental image must be established at the outset of further high accuracy simulations or calculations. Furthermore, if simulation is to be used in context of highly automated processes or high-throughput optimization, the process of finding this correspondence itself must be automated. In this work, "ingrained," an open-source automation framework which solves for this correspondence and fuses atomic resolution image simulations into the experimental images to which they correspond, is introduced. Herein, the overall "ingrained" workflow, focusing on its application to interface structure approximations, and the development of an experimentally rationalized forward model for scanning tunneling microscopy simulation are described.
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Affiliation(s)
- Eric Schwenker
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Venkata Surya Chaitanya Kolluru
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Jinglong Guo
- Department of Physics, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Rui Zhang
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Xiaobing Hu
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Qiucheng Li
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Joshua T Paul
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Mark C Hersam
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Robert Klie
- Department of Physics, University of Illinois Chicago, Chicago, IL, 60607, USA
| | - Jeffrey R Guest
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Maria K Y Chan
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
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17
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Arslan Irmak E, Liu P, Bals S, Van Aert S. 3D Atomic Structure of Supported Metallic Nanoparticles Estimated from 2D ADF STEM Images: A Combination of Atom-Counting and a Local Minima Search Algorithm. SMALL METHODS 2021; 5:e2101150. [PMID: 34928008 DOI: 10.1002/smtd.202101150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/22/2021] [Indexed: 06/14/2023]
Abstract
Determining the 3D atomic structure of nanoparticles (NPs) is critical to understand their structure-dependent properties. It is hereby important to perform such analyses under conditions relevant for the envisioned application. Here, the 3D structure of supported Au NPs at high temperature, which is of importance to understand their behavior during catalytic reactions, is investigated. To overcome limitations related to conventional high-resolution electron tomography at high temperature, 3D characterization of NPs with atomic resolution has been performed by applying atom-counting using atomic resolution annular dark-field scanning transmission electron microscopy (ADF STEM) images followed by structural relaxation. However, at high temperatures, thermal displacements, which affect the ADF STEM intensities, should be taken into account. Moreover, it is very likely that the structure of an NP investigated at elevated temperature deviates from a ground state configuration, which is difficult to determine using purely computational energy minimization approaches. In this paper, an optimized approach is therefore proposed using an iterative local minima search algorithm followed by molecular dynamics structural relaxation of candidate structures associated with each local minimum. In this manner, it becomes possible to investigate the 3D atomic structure of supported NPs, which may deviate from their ground state configuration.
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Affiliation(s)
- Ece Arslan Irmak
- EMAT and NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Pei Liu
- EMAT and NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sara Bals
- EMAT and NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sandra Van Aert
- EMAT and NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
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18
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Modelling ADF STEM images using elliptical Gaussian peaks and its effects on the quantification of structure parameters in the presence of sample tilt. Ultramicroscopy 2021; 230:113391. [PMID: 34600202 DOI: 10.1016/j.ultramic.2021.113391] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 09/03/2021] [Accepted: 09/09/2021] [Indexed: 11/20/2022]
Abstract
A small sample tilt away from a main zone axis orientation results in an elongation of the atomic columns in ADF STEM images. An often posed research question is therefore whether the ADF STEM image intensities of tilted nanomaterials should be quantified using a parametric imaging model consisting of elliptical rather than the currently used symmetrical peaks. To this purpose, simulated ADF STEM images corresponding to different amounts of sample tilt are studied using a parametric imaging model that consists of superimposed 2D elliptical Gaussian peaks on the one hand and symmetrical Gaussian peaks on the other hand. We investigate the quantification of structural parameters such as atomic column positions and scattering cross sections using both parametric imaging models. In this manner, we quantitatively study what can be gained from this elliptical model for quantitative ADF STEM, despite the increased parameter space and computational effort. Although a qualitative improvement can be achieved, no significant quantitative improvement in the estimated structure parameters is achieved by the elliptical model as compared to the symmetrical model. The decrease in scattering cross sections with increasing sample tilt is even identical for both types of parametric imaging models. This impedes direct comparison with zone axis image simulations. Nonetheless, we demonstrate how reliable atom-counting can still be achieved in the presence of small sample tilt.
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19
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Liu JJ. Advances and Applications of Atomic-Resolution Scanning Transmission Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-53. [PMID: 34414878 DOI: 10.1017/s1431927621012125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Although scanning transmission electron microscopy (STEM) images of individual heavy atoms were reported 50 years ago, the applications of atomic-resolution STEM imaging became wide spread only after the practical realization of aberration correctors on field-emission STEM/TEM instruments to form sub-Ångstrom electron probes. The innovative designs and advances of electron optical systems, the fundamental understanding of electron–specimen interaction processes, and the advances in detector technology all played a major role in achieving the goal of atomic-resolution STEM imaging of practical materials. It is clear that tremendous advances in computer technology and electronics, image acquisition and processing algorithms, image simulations, and precision machining synergistically made atomic-resolution STEM imaging routinely accessible. It is anticipated that further hardware/software development is needed to achieve three-dimensional atomic-resolution STEM imaging with single-atom chemical sensitivity, even for electron-beam-sensitive materials. Artificial intelligence, machine learning, and big-data science are expected to significantly enhance the impact of STEM and associated techniques on many research fields such as materials science and engineering, quantum and nanoscale science, physics and chemistry, and biology and medicine. This review focuses on advances of STEM imaging from the invention of the field-emission electron gun to the realization of aberration-corrected and monochromated atomic-resolution STEM and its broad applications.
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Affiliation(s)
- Jingyue Jimmy Liu
- Department of Physics, Arizona State University, Tempe, AZ85287, USA
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20
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Mahr C, Dworzak A, Schowalter M, Oezaslan M, Rosenauer A. Quantitative 3D Characterization of Nanoporous Gold Nanoparticles by Transmission Electron Microscopy. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:678-686. [PMID: 34085625 DOI: 10.1017/s1431927621000519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Quantitative structural characterization of nanomaterials is important to tailor their functional properties. Corrosion of AgAu-alloy nanoparticles (NPs) results in porous structures, making them interesting for applications especially in the fields of catalysis and surface-enhanced Raman spectroscopy. For the present report, structures of dealloyed NPs were reconstructed three-dimensionally using scanning transmission electron microscopy tomography. These reconstructions were evaluated quantitatively, revealing structural information such as pore size, porosity, specific surface area, and tortuosity. Results show significant differences compared to the structure of dealloyed bulk samples and can be used as input for simulations of diffusion or mass transport processes, for example, in catalytic applications.
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Affiliation(s)
- Christoph Mahr
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstr. 1, 28359Bremen, Germany
| | - Alexandra Dworzak
- Technical Electrocatalysis Laboratory, Institute of Technical Chemistry, Technical University of Braunschweig, Franz-Liszt-Str. 35a, 38106Braunschweig, Germany
- Institute of Chemistry, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129Oldenburg, Germany
| | - Marco Schowalter
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstr. 1, 28359Bremen, Germany
| | - Mehtap Oezaslan
- Technical Electrocatalysis Laboratory, Institute of Technical Chemistry, Technical University of Braunschweig, Franz-Liszt-Str. 35a, 38106Braunschweig, Germany
- Institute of Chemistry, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129Oldenburg, Germany
| | - Andreas Rosenauer
- Institute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, 28359Bremen, Germany
- MAPEX Center for Materials and Processes, University of Bremen, Bibliothekstr. 1, 28359Bremen, Germany
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21
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Jiang H, Xu J, Zhang Q, Yu Q, Shen L, Liu M, Sun Y, Cao C, Su D, Bai H, Meng S, Sun B, Gu L, Wang W. Direct observation of atomic-level fractal structure in a metallic glass membrane. Sci Bull (Beijing) 2021; 66:1312-1318. [PMID: 36654153 DOI: 10.1016/j.scib.2021.02.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/15/2021] [Accepted: 01/27/2021] [Indexed: 01/20/2023]
Abstract
Determination and conceptualization of atomic structures of metallic glasses or amorphous alloys remain a grand challenge. Structural models proposed for bulk metallic glasses are still controversial owing to experimental difficulties in directly imaging the atom positions in three-dimensional structures. With the advanced atomic-resolution imaging, here we directly observed the atomic arrangements in atomically thin metallic glassy membranes obtained by vapor deposition. The atomic packing in the amorphous membrane is shown to have a fractal characteristic, with the fractal dimension depending on the atomic density. Locally, the atomic configuration for the metallic glass membrane is composed of many types of polygons with the bonding angles concentrated on 45°-55°. The fractal atomic structure is consistent with the analysis by the percolation theory, and may account for the enhanced relaxation dynamics and the easiness of glass transition as reported for the thin metallic glassy films or glassy surface.
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Affiliation(s)
- Hongyu Jiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jiyu Xu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Qinghua Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Qian Yu
- Department of Materials Science & Engineering, Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China
| | - Laiquan Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - Ming Liu
- Qian Xuesen Laboratory of Space Technology, Beijing 100094, China
| | - Yitao Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chengrong Cao
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Dong Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Haiyang Bai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baoan Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Lin Gu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Weihua Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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22
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MacArthur KE, Clement A, Heggen M, Dunin-Borkowski RE. Combining quantitative ADF STEM with SiN x membrane-based MEMS devices: A simulation study with Pt nanoparticles. Ultramicroscopy 2021; 231:113270. [PMID: 33888359 DOI: 10.1016/j.ultramic.2021.113270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 03/24/2021] [Accepted: 04/05/2021] [Indexed: 11/26/2022]
Abstract
Computer simulations are used to assess the influence of a 20-nm-thick SiNx membrane on the quantification of atomic-resolution annular dark-field (ADF) scanning transmission electron microscopy images of Pt nanoparticles. The discussions include the effect of different nanoparticle/membrane arrangements, accelerating voltage, nanoparticle thickness and the presence of adjacent atomic columns on the accuracy with which the number of Pt atoms in each atom column can be counted. The results, which are based on the use of ADF scattering cross-sections, show that an accuracy of better than a single atom is attainable at 200 and 300 kV. At 80kV, the scattering in a typical SiNx membrane is sufficiently strong that the best possible atom counting accuracy is reduced to +/- 2 atoms. The implications of the work for quantitative studies of Pt nanoparticles imaged through SiNx membranes are discussed.
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Affiliation(s)
- Katherine E MacArthur
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany.
| | - Antoine Clement
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany; Ecole Nationale Supérieure des Mines de Nancy, Campus Artem, BP 14234, 92 rue du Sergent Blandan, 54042 Nancy cedex, France
| | - Marc Heggen
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
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23
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MacArthur KE, Yankovich AB, Béché A, Luysberg M, Brown HG, Findlay SD, Heggen M, Allen LJ. Optimizing Experimental Conditions for Accurate Quantitative Energy-Dispersive X-ray Analysis of Interfaces at the Atomic Scale. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-15. [PMID: 33843542 DOI: 10.1017/s1431927621000246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The invention of silicon drift detectors has resulted in an unprecedented improvement in detection efficiency for energy-dispersive X-ray (EDX) spectroscopy in the scanning transmission electron microscope. The result is numerous beautiful atomic-scale maps, which provide insights into the internal structure of a variety of materials. However, the task still remains to understand exactly where the X-ray signal comes from and how accurately it can be quantified. Unfortunately, when crystals are aligned with a low-order zone axis parallel to the incident beam direction, as is necessary for atomic-resolution imaging, the electron beam channels. When the beam becomes localized in this way, the relationship between the concentration of a particular element and its spectroscopic X-ray signal is generally nonlinear. Here, we discuss the combined effect of both spatial integration and sample tilt for ameliorating the effects of channeling and improving the accuracy of EDX quantification. Both simulations and experimental results will be presented for a perovskite-based oxide interface. We examine how the scattering and spreading of the electron beam can lead to erroneous interpretation of interface compositions, and what approaches can be made to improve our understanding of the underlying atomic structure.
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Affiliation(s)
- Katherine E MacArthur
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Andrew B Yankovich
- Department of Physics, Chalmers University of Technology, SE-412 96Gothenburg, Sweden
| | - Armand Béché
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020Antwerp, Belgium
| | - Martina Luysberg
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Hamish G Brown
- National Centre for Electron Microscopy, the Molecular Foundry, Lawrence Berkeley National Lab, Berkeley, CA94720, USA
| | - Scott D Findlay
- School of Physics and Astronomy, Monash University, Clayton, VIC3800, Australia
| | - Marc Heggen
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich52425, Germany
| | - Leslie J Allen
- School of Physics, University of Melbourne, Parkville, VIC3010, Australia
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24
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Zhang C, Feng J, Yankovich AB, Kvit A, Berkels B, Voyles PM. Optimizing Nonrigid Registration for Scanning Transmission Electron Microscopy Image Series. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:90-98. [PMID: 33222719 DOI: 10.1017/s1431927620024708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Achieving sub-picometer precision measurements of atomic column positions in high-resolution scanning transmission electron microscope images using nonrigid registration (NRR) and averaging of image series requires careful optimization of experimental conditions and the parameters of the registration algorithm. On experimental data from SrTiO3 [100], sub-pm precision requires alignment of the sample to the zone axis to within 1 mrad tilt and sample drift of less than 1 nm/min. At fixed total electron dose for the series, precision in the fast scan direction improves with shorter pixel dwell time to the limit of our microscope hardware, but the best precision along the slow scan direction occurs at 6 μs/px dwell time. Within the NRR algorithm, the “smoothness factor” that penalizes large estimated shifts is the most important parameter for sub-pm precision, but in general, the precision of NRR images is robust over a wide range of parameters.
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Affiliation(s)
- Chenyu Zhang
- Department of Materials Science and Engineering, University of Wisconsin - Madison, 1509 University Avenue, Madison, WI53706, USA
| | - Jie Feng
- Department of Materials Science and Engineering, University of Wisconsin - Madison, 1509 University Avenue, Madison, WI53706, USA
| | - Andrew B Yankovich
- Department of Materials Science and Engineering, University of Wisconsin - Madison, 1509 University Avenue, Madison, WI53706, USA
| | - Alexander Kvit
- Department of Materials Science and Engineering, University of Wisconsin - Madison, 1509 University Avenue, Madison, WI53706, USA
| | - Benjamin Berkels
- Aachen Institute for Advanced Study in Computational Engineering Science, RWTH Aachen University, Schinkelstr. 2, 52056Aachen, Germany
| | - Paul M Voyles
- Department of Materials Science and Engineering, University of Wisconsin - Madison, 1509 University Avenue, Madison, WI53706, USA
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25
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Liu P, Arslan Irmak E, De Backer A, De Wael A, Lobato I, Béché A, Van Aert S, Bals S. Three-dimensional atomic structure of supported Au nanoparticles at high temperature. NANOSCALE 2021; 13:1770-1776. [PMID: 33432963 DOI: 10.1039/d0nr08664a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Au nanoparticles (NPs) deposited on CeO2 are extensively used as thermal catalysts since the morphology of the NPs is expected to be stable at elevated temperatures. Although it is well known that the activity of Au NPs depends on their size and surface structure, their three-dimensional (3D) structure at the atomic scale has not been completely characterized as a function of temperature. In this paper, we overcome the limitations of conventional electron tomography by combining atom counting applied to aberration-corrected scanning transmission electron microscopy images and molecular dynamics relaxation. In this manner, we are able to perform an atomic resolution 3D investigation of supported Au NPs. Our results enable us to characterize the 3D equilibrium structure of single NPs as a function of temperature. Moreover, the dynamic 3D structural evolution of the NPs at high temperatures, including surface layer jumping and crystalline transformations, has been studied.
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Affiliation(s)
- Pei Liu
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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26
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De Wael A, De Backer A, Van Aert S. Hidden Markov model for atom-counting from sequential ADF STEM images: Methodology, possibilities and limitations. Ultramicroscopy 2020; 219:113131. [PMID: 33091707 DOI: 10.1016/j.ultramic.2020.113131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 10/23/2022]
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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Affiliation(s)
- Annelies De Wael
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Annick De Backer
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium.
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27
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De Wael A, De Backer A, Jones L, Varambhia A, Nellist PD, Van Aert S. Measuring Dynamic Structural Changes of Nanoparticles at the Atomic Scale Using Scanning Transmission Electron Microscopy. PHYSICAL REVIEW LETTERS 2020; 124:106105. [PMID: 32216442 DOI: 10.1103/physrevlett.124.106105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/30/2020] [Indexed: 06/10/2023]
Abstract
We propose a new method to measure atomic scale dynamics of nanoparticles from experimental high-resolution annular dark field scanning transmission electron microscopy images. By using the so-called hidden Markov model, which explicitly models the possibility of structural changes, the number of atoms in each atomic column can be quantified over time. This newly proposed method outperforms the current atom-counting procedure and enables the determination of the probabilities and cross sections for surface diffusion. This method is therefore of great importance for revealing and quantifying the atomic structure when it evolves over time via adatom dynamics, surface diffusion, beam effects, or during in situ experiments.
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Affiliation(s)
- Annelies De Wael
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Annick De Backer
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Lewys Jones
- Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, United Kingdom
- Advanced Microscopy Laboratory, Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Dublin 2, Ireland
- School of Physics, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Aakash Varambhia
- Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, United Kingdom
| | - Peter D Nellist
- Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, United Kingdom
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
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28
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Composition determination of semiconductor alloys towards atomic accuracy by HAADF-STEM. Ultramicroscopy 2019; 200:84-96. [PMID: 30844539 DOI: 10.1016/j.ultramic.2019.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 12/21/2018] [Accepted: 02/12/2019] [Indexed: 11/23/2022]
Abstract
This paper presents a comprehensive investigation of an extended method to determine composition of materials by scanning transmission electron microscopy (STEM) high angle annular darkfield (HAADF) images and using complementary multislice simulations. The main point is to understand the theoretical capabilities of the algorithm and address the intrinsic limitations of using STEM HAADF intensities for composition determination. A special focus is the potential of the method regarding single-atom accuracy. All-important experimental parameters are included into the multislice simulations to ensure the best possible fit between simulation and experiment. To demonstrate the capabilities of the extended method, results for three different technical important semiconductor samples are presented. Overall the method shows a high lateral resolution combined with a high accuracy towards single-atom accuracy.
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29
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Altantzis T, Lobato I, De Backer A, Béché A, Zhang Y, Basak S, Porcu M, Xu Q, Sánchez-Iglesias A, Liz-Marzán LM, Van Tendeloo G, Van Aert S, Bals S. Three-Dimensional Quantification of the Facet Evolution of Pt Nanoparticles in a Variable Gaseous Environment. NANO LETTERS 2019; 19:477-481. [PMID: 30540912 PMCID: PMC6437648 DOI: 10.1021/acs.nanolett.8b04303] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Pt nanoparticles play an essential role in a wide variety of catalytic reactions. The activity of the particles strongly depends on their three-dimensional (3D) structure and exposed facets, as well as on the reactive environment. High-resolution electron microscopy has often been used to characterize nanoparticle catalysts but unfortunately most observations so far have been either performed in vacuum and/or using conventional (2D) in situ microscopy. The latter however does not provide direct 3D morphological information. We have implemented a quantitative methodology to measure variations of the 3D atomic structure of nanoparticles under the flow of a selected gas. We were thereby able to quantify refaceting of Pt nanoparticles with atomic resolution during various oxidation-reduction cycles. In a H2 environment, a more faceted surface morphology of the particles was observed with {100} and {111} planes being dominant. On the other hand, in O2 the percentage of {100} and {111} facets decreased and a significant increase of higher order facets was found, resulting in a more rounded morphology. This methodology opens up new opportunities toward in situ characterization of catalytic nanoparticles because for the first time it enables one to directly measure 3D morphology variations at the atomic scale in a specific gaseous reaction environment.
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Affiliation(s)
- Thomas Altantzis
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Ivan Lobato
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Annick De Backer
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Armand Béché
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Yang Zhang
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Shibabrata Basak
- DENSsolutions, Informaticalaan 12, Delft, 2628ZD, The Netherlands
| | - Mauro Porcu
- DENSsolutions, Informaticalaan 12, Delft, 2628ZD, The Netherlands
| | - Qiang Xu
- DENSsolutions, Informaticalaan 12, Delft, 2628ZD, The Netherlands
| | - Ana Sánchez-Iglesias
- Bionanoplasmonics
Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20014 Donostia - San Sebastian, Spain
| | - Luis M. Liz-Marzán
- Bionanoplasmonics
Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20014 Donostia - San Sebastian, Spain
- Ikerbasque,
Basque Foundation for Science, 48013 Bilbao, Spain
| | - Gustaaf Van Tendeloo
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sandra Van Aert
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sara Bals
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- E-mail:
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30
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Imaoka T, Toyonaga T, Morita M, Haruta N, Yamamoto K. Isomerizations of a Pt 4 cluster revealed by spatiotemporal microscopic analysis. Chem Commun (Camb) 2019; 55:4753-4756. [PMID: 30897188 DOI: 10.1039/c9cc00530g] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We now report the first direct observation of the fluxional nature in which the four-atomic platinum cluster (Pt4) randomly walks through several isomers. Time-lapse analysis by a Cs-corrected transmission electron microscope allowed us to acquire the atomic coordinates at a sub-angstrom space resolution and 0.2 s time resolution for each cluster isomer. The analysis revealed that the isomerization follows a simple first-order kinetic model.
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Affiliation(s)
- Takane Imaoka
- Laboratory for Chemistry and Life Science (CLS), Institute of Innovative Research (IIR), Tokyo Institute of Technology, Yokohama 226-8503, Japan.
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31
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Varambhia A, Jones L, London A, Ozkaya D, Nellist PD, Lozano-Perez S. Determining EDS and EELS partial cross-sections from multiple calibration standards to accurately quantify bi-metallic nanoparticles using STEM. Micron 2018; 113:69-82. [DOI: 10.1016/j.micron.2018.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/22/2018] [Accepted: 06/22/2018] [Indexed: 11/15/2022]
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32
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Fatermans J, den Dekker AJ, Müller-Caspary K, Lobato I, O'Leary CM, Nellist PD, Van Aert S. Single Atom Detection from Low Contrast-to-Noise Ratio Electron Microscopy Images. PHYSICAL REVIEW LETTERS 2018; 121:056101. [PMID: 30118288 DOI: 10.1103/physrevlett.121.056101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/15/2018] [Indexed: 06/08/2023]
Abstract
Single atom detection is of key importance to solving a wide range of scientific and technological problems. The strong interaction of electrons with matter makes transmission electron microscopy one of the most promising techniques. In particular, aberration correction using scanning transmission electron microscopy has made a significant step forward toward detecting single atoms. However, to overcome radiation damage, related to the use of high-energy electrons, the incoming electron dose should be kept low enough. This results in images exhibiting a low signal-to-noise ratio and extremely weak contrast, especially for light-element nanomaterials. To overcome this problem, a combination of physics-based model fitting and the use of a model-order selection method is proposed, enabling one to detect single atoms with high reliability.
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Affiliation(s)
- J Fatermans
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Imec-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - A J den Dekker
- Imec-Vision Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
- Delft Center for Systems and Control (DCSC), Delft University of Technology, Mekelweg 2, 2628 CD Delft, Netherlands
| | - K Müller-Caspary
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - I Lobato
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - C M O'Leary
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - P D Nellist
- Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
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33
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Guzzinati G, Altantzis T, Batuk M, De Backer A, Lumbeeck G, Samaee V, Batuk D, Idrissi H, Hadermann J, Van Aert S, Schryvers D, Verbeeck J, Bals S. Recent Advances in Transmission Electron Microscopy for Materials Science at the EMAT Lab of the University of Antwerp. MATERIALS (BASEL, SWITZERLAND) 2018; 11:E1304. [PMID: 30060556 PMCID: PMC6117696 DOI: 10.3390/ma11081304] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 01/13/2023]
Abstract
The rapid progress in materials science that enables the design of materials down to the nanoscale also demands characterization techniques able to analyze the materials down to the same scale, such as transmission electron microscopy. As Belgium's foremost electron microscopy group, among the largest in the world, EMAT is continuously contributing to the development of TEM techniques, such as high-resolution imaging, diffraction, electron tomography, and spectroscopies, with an emphasis on quantification and reproducibility, as well as employing TEM methodology at the highest level to solve real-world materials science problems. The lab's recent contributions are presented here together with specific case studies in order to highlight the usefulness of TEM to the advancement of materials science.
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Affiliation(s)
- Giulio Guzzinati
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Thomas Altantzis
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Maria Batuk
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Annick De Backer
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Gunnar Lumbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Vahid Samaee
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Dmitry Batuk
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Hosni Idrissi
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
- Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Louvain-la-Neuve 1348, Belgium.
| | - Joke Hadermann
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | | | - Johan Verbeeck
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
| | - Sara Bals
- EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
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34
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Pennycook SJ, Li C, Li M, Tang C, Okunishi E, Varela M, Kim YM, Jang JH. Material structure, properties, and dynamics through scanning transmission electron microscopy. J Anal Sci Technol 2018; 9:11. [PMID: 31258949 PMCID: PMC6560782 DOI: 10.1186/s40543-018-0142-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/14/2018] [Indexed: 12/03/2022] Open
Abstract
Scanning transmission electron microscopy (STEM) has advanced rapidly in the last decade thanks to the ability to correct the major aberrations of the probe-forming lens. Now, atomic-sized beams are routine, even at accelerating voltages as low as 40 kV, allowing knock-on damage to be minimized in beam sensitive materials. The aberration-corrected probes can contain sufficient current for high-quality, simultaneous, imaging and analysis in multiple modes. Atomic positions can be mapped with picometer precision, revealing ferroelectric domain structures, composition can be mapped by energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS), and charge transfer can be tracked unit cell by unit cell using the EELS fine structure. Furthermore, dynamics of point defects can be investigated through rapid acquisition of multiple image scans. Today STEM has become an indispensable tool for analytical science at the atomic level, providing a whole new level of insights into the complex interplays that control material properties.
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Affiliation(s)
- Stephen J. Pennycook
- Department of Materials Science and Engineering, National University of Singapore, Block EA 07-14, 9 Engineering Drive 1, Singapore, 117575 Singapore
| | - Changjian Li
- Department of Materials Science and Engineering, National University of Singapore, Block EA 07-14, 9 Engineering Drive 1, Singapore, 117575 Singapore
| | - Mengsha Li
- Department of Materials Science and Engineering, National University of Singapore, Block EA 07-14, 9 Engineering Drive 1, Singapore, 117575 Singapore
| | - Chunhua Tang
- Department of Materials Science and Engineering, National University of Singapore, Block EA 07-14, 9 Engineering Drive 1, Singapore, 117575 Singapore
| | | | - Maria Varela
- Dpt. Física de Materiales, Instituto de Magnetismo Aplicado & Instituto Pluridisciplinar, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon, 16419 Republic of Korea
| | - Jae Hyuck Jang
- Electron Microscopy Research Center, Korea Basic Science Institute, Daejeon, 34133 South Korea
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35
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MacArthur KE, Heggen M, Dunin-Borkowski RE. Differentiating the structure of PtNi octahedral nanoparticles through combined ADF-EDX simulations. ACTA ACUST UNITED AC 2018; 4:2. [PMID: 29497598 PMCID: PMC5820384 DOI: 10.1186/s40679-018-0053-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/10/2018] [Indexed: 11/18/2022]
Abstract
Advances in catalysis rely on the synthesis and characterisation of nanoparticles that have tailored structures and compositions. Although energy-dispersive X-ray (EDX) spectroscopy can be used to study local variations in the compositions of individual supported nanoparticles on the atomic-scale in the scanning transmission electron microscope, electron beam induced damage and contamination can preclude the use of long exposure times and tomographic approaches. Here, we perform simulations of EDX maps of seven different octahedral PtNi nanoparticles for a selection of crystallographic orientations and tilts, to evaluate which of them can be distinguished from elemental mapping performed in only one orientation.
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Affiliation(s)
- Katherine E MacArthur
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Marc Heggen
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rafal E Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute, Forschungszentrum Jülich, 52425 Jülich, Germany
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36
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Martinez GT, van den Bos KHW, Alania M, Nellist PD, Van Aert S. Thickness dependence of scattering cross-sections in quantitative scanning transmission electron microscopy. Ultramicroscopy 2018; 187:84-92. [PMID: 29413416 DOI: 10.1016/j.ultramic.2018.01.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 11/16/2022]
Abstract
In quantitative scanning transmission electron microscopy (STEM), scattering cross-sections have been shown to be very sensitive to the number of atoms in a column and its composition. They correspond to the integrated intensity over the atomic column and they outperform other measures. As compared to atomic column peak intensities, which saturate at a given thickness, scattering cross-sections increase monotonically. A study of the electron wave propagation is presented to explain the sensitivity of the scattering cross-sections. Based on the multislice algorithm, we analyse the wave propagation inside the crystal and its link to the scattered signal for the different probe positions contained in the scattering cross-section for detector collection in the low-, middle- and high-angle regimes. The influence to the signal from scattering of neighbouring columns is also discussed.
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Affiliation(s)
- G T Martinez
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020, Antwerp, Belgium
| | - K H W van den Bos
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020, Antwerp, Belgium
| | - M Alania
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020, Antwerp, Belgium
| | - P D Nellist
- Department of Materials, Oxford University, Parks Road, Oxford OX1 3PH, United Kingdom
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Gronenborgerlaan 171, 2020, Antwerp, Belgium.
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37
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Alania M, Lobato I, Van Aert S. Frozen lattice and absorptive model for high angle annular dark field scanning transmission electron microscopy: A comparison study in terms of integrated intensity and atomic column position measurement. Ultramicroscopy 2017; 184:188-198. [PMID: 28942200 DOI: 10.1016/j.ultramic.2017.08.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 11/15/2022]
Abstract
In this paper, both the frozen lattice (FL) and the absorptive potential (AP) approximation models are compared in terms of the integrated intensity and the precision with which atomic columns can be located from an image acquired using high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM). The comparison is made for atoms of Cu, Ag, and Au. The integrated intensity is computed for both an isolated atomic column and an atomic column inside an FCC structure. The precision has been computed using the so-called Cramér-Rao Lower Bound (CRLB), which provides a theoretical lower bound on the variance with which parameters can be estimated. It is shown that the AP model results into accurate measurements for the integrated intensity only for small detector ranges under relatively low angles and for small thicknesses. In terms of the attainable precision, both methods show similar results indicating picometer range precision under realistic experimental conditions.
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Affiliation(s)
- M Alania
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - I Lobato
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - S Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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38
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The impact of STEM aberration correction on materials science. Ultramicroscopy 2017; 180:22-33. [DOI: 10.1016/j.ultramic.2017.03.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 03/04/2017] [Accepted: 03/16/2017] [Indexed: 11/22/2022]
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De Backer A, Jones L, Lobato I, Altantzis T, Goris B, Nellist PD, Bals S, Van Aert S. Three-dimensional atomic models from a single projection using Z-contrast imaging: verification by electron tomography and opportunities. NANOSCALE 2017; 9:8791-8798. [PMID: 28621785 DOI: 10.1039/c7nr02656k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In order to fully exploit structure-property relations of nanomaterials, three-dimensional (3D) characterization at the atomic scale is often required. In recent years, the resolution of electron tomography has reached the atomic scale. However, such tomography typically requires several projection images demanding substantial electron dose. A newly developed alternative circumvents this by counting the number of atoms across a single projection. These atom counts can be used to create an initial atomic model with which an energy minimization can be applied to obtain a relaxed 3D reconstruction of the nanoparticle. Here, we compare, at the atomic scale, this single projection reconstruction approach with tomography and find an excellent agreement. This new approach allows for the characterization of beam-sensitive materials or where the acquisition of a tilt series is impossible. As an example, the utility is illustrated by the 3D atomic scale characterization of a nanodumbbell on an in situ heating holder of limited tilt range.
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Affiliation(s)
- A De Backer
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
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Alania M, Altantzis T, De Backer A, Lobato I, Bals S, Van Aert S. Depth sectioning combined with atom-counting in HAADF STEM to retrieve the 3D atomic structure. Ultramicroscopy 2017; 177:36-42. [DOI: 10.1016/j.ultramic.2016.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/21/2016] [Accepted: 11/04/2016] [Indexed: 11/30/2022]
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Gonnissen J, De Backer A, den Dekker A, Sijbers J, Van Aert S. Atom-counting in High Resolution Electron Microscopy:TEM or STEM – That's the question. Ultramicroscopy 2017; 174:112-120. [DOI: 10.1016/j.ultramic.2016.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/14/2016] [Accepted: 10/25/2016] [Indexed: 11/24/2022]
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Oxley MP, Lupini AR, Pennycook SJ. Ultra-high resolution electron microscopy. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:026101. [PMID: 28008874 DOI: 10.1088/1361-6633/80/2/026101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The last two decades have seen dramatic advances in the resolution of the electron microscope brought about by the successful correction of lens aberrations that previously limited resolution for most of its history. We briefly review these advances, the achievement of sub-Ångstrom resolution and the ability to identify individual atoms, their bonding configurations and even their dynamics and diffusion pathways. We then present a review of the basic physics of electron scattering, lens aberrations and their correction, and an approximate imaging theory for thin crystals which provides physical insight into the various different imaging modes. Then we proceed to describe a more exact imaging theory starting from Yoshioka's formulation and covering full image simulation methods using Bloch waves, the multislice formulation and the frozen phonon/quantum excitation of phonons models. Delocalization of inelastic scattering has become an important limiting factor at atomic resolution. We therefore discuss this issue extensively, showing how the full-width-half-maximum is the appropriate measure for predicting image contrast, but the diameter containing 50% of the excitation is an important measure of the range of the interaction. These two measures can differ by a factor of 5, are not a simple function of binding energy, and full image simulations are required to match to experiment. The Z-dependence of annular dark field images is also discussed extensively, both for single atoms and for crystals, and we show that temporal incoherence must be included accurately if atomic species are to be identified through matching experimental intensities to simulations. Finally we mention a few promising directions for future investigation.
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Affiliation(s)
- Mark P Oxley
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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De Wael A, De Backer A, Jones L, Nellist PD, Van Aert S. Hybrid statistics-simulations based method for atom-counting from ADF STEM images. Ultramicroscopy 2017; 177:69-77. [PMID: 28292688 DOI: 10.1016/j.ultramic.2017.01.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/05/2017] [Accepted: 01/21/2017] [Indexed: 10/20/2022]
Abstract
A hybrid statistics-simulations based method for atom-counting from annular dark field scanning transmission electron microscopy (ADF STEM) images of monotype crystalline nanostructures is presented. Different atom-counting methods already exist for model-like systems. However, the increasing relevance of radiation damage in the study of nanostructures demands a method that allows atom-counting from low dose images with a low signal-to-noise ratio. Therefore, the hybrid method directly includes prior knowledge from image simulations into the existing statistics-based method for atom-counting, and accounts in this manner for possible discrepancies between actual and simulated experimental conditions. It is shown by means of simulations and experiments that this hybrid method outperforms the statistics-based method, especially for low electron doses and small nanoparticles. The analysis of a simulated low dose image of a small nanoparticle suggests that this method allows for far more reliable quantitative analysis of beam-sensitive materials.
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Affiliation(s)
- Annelies De Wael
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | - Annick De Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Lewys Jones
- Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, UK
| | - Peter D Nellist
- Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, UK
| | - Sandra Van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
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De Backer A, van den Bos K, Van den Broek W, Sijbers J, Van Aert S. StatSTEM: An efficient approach for accurate and precise model-based quantification of atomic resolution electron microscopy images. Ultramicroscopy 2016; 171:104-116. [DOI: 10.1016/j.ultramic.2016.08.018] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/22/2016] [Accepted: 08/29/2016] [Indexed: 10/21/2022]
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Wang Z, Ning S, Fujita T, Hirata A, Chen M. Unveiling Three-Dimensional Stacking Sequences of 1T Phase MoS 2 Monolayers by Electron Diffraction. ACS NANO 2016; 10:10308-10316. [PMID: 27788327 DOI: 10.1021/acsnano.6b05958] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The phase transition between semiconducting 1H to metallic 1T phases in monolayered transition metal dichalcogenides (TMDs) essentially involves three-dimensional (3D) structure changes of asymmetric relocations of S atoms at the top and bottom of the one-unit-cell crystals. Even though the phase transition has a profound influence on properties and applications of 2D TMDs, a viable approach to experimentally characterize the stacking sequences of the vertically asymmetrical 1T phase is still not available. Here, we report an electron diffraction method based on dynamic electron scattering to characterize the stacking sequences of 1T MoS2 monolayers. This study provides an approach to unveil the 3D structure of 2D crystals and to explore the underlying mechanisms of semiconductor-to-metal transition of monolayer TMDs.
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Affiliation(s)
| | - Shoucong Ning
- Department of Mechanical and Aerospace Engineering, School of Engineering, Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong SAR
| | | | | | - Mingwei Chen
- CREST, JST , 4-1-8 Honcho Kawaguchi, Saitama 332-0012, Japan
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MOYON F, HERNANDEZ-MALDONADO D, ROBERTSON M, ETIENNE A, CASTRO C, LEFEBVRE W. Reverse Monte Carlo reconstruction algorithm for discrete electron tomography based on HAADF-STEM atom counting. J Microsc 2016; 265:73-80. [DOI: 10.1111/jmi.12464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/04/2016] [Accepted: 07/31/2016] [Indexed: 11/28/2022]
Affiliation(s)
- F. MOYON
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS; Groupe de Physique des Matériaux; Rouen France
| | | | - M.D. ROBERTSON
- Department of Physics; Acadia University; Wolfville Nova Scotia Canada
| | - A. ETIENNE
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS; Groupe de Physique des Matériaux; Rouen France
| | - C. CASTRO
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS; Groupe de Physique des Matériaux; Rouen France
| | - W. LEFEBVRE
- Normandie Univ, UNIROUEN, INSA Rouen, CNRS; Groupe de Physique des Matériaux; Rouen France
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van den Bos KHW, De Backer A, Martinez GT, Winckelmans N, Bals S, Nellist PD, Van Aert S. Unscrambling Mixed Elements using High Angle Annular Dark Field Scanning Transmission Electron Microscopy. PHYSICAL REVIEW LETTERS 2016; 116:246101. [PMID: 27367396 DOI: 10.1103/physrevlett.116.246101] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Indexed: 05/16/2023]
Abstract
The development of new nanocrystals with outstanding physicochemical properties requires a full three-dimensional (3D) characterization at the atomic scale. For homogeneous nanocrystals, counting the number of atoms in each atomic column from high angle annular dark field scanning transmission electron microscopy images has been shown to be a successful technique to get access to this 3D information. However, technologically important nanostructures often consist of more than one chemical element. In order to extend atom counting to heterogeneous materials, a new atomic lensing model is presented. This model takes dynamical electron diffraction into account and opens up new possibilities for unraveling the 3D composition at the atomic scale. Here, the method is applied to determine the 3D structure of Au@Ag core-shell nanorods, but it is applicable to a wide range of heterogeneous complex nanostructures.
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Affiliation(s)
| | - Annick De Backer
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Gerardo T Martinez
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Naomi Winckelmans
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sara Bals
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Peter D Nellist
- Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, United Kingdom
| | - Sandra Van Aert
- EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
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STEM image simulation with hybrid CPU/GPU programming. Ultramicroscopy 2016; 166:1-8. [PMID: 27093687 DOI: 10.1016/j.ultramic.2016.04.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 03/28/2016] [Accepted: 04/08/2016] [Indexed: 11/20/2022]
Abstract
STEM image simulation is achieved via hybrid CPU/GPU programming under parallel algorithm architecture to speed up calculation on a personal computer (PC). To utilize the calculation power of a PC fully, the simulation is performed using the GPU core and multi-CPU cores at the same time to significantly improve efficiency. GaSb and an artificial GaSb/InAs interface with atom diffusion have been used to verify the computation.
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Direct investigation of (sub-) surface preparation artifacts in GaAs based materials by FIB sectioning. Ultramicroscopy 2016; 163:19-30. [DOI: 10.1016/j.ultramic.2016.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 12/27/2015] [Accepted: 01/23/2016] [Indexed: 11/20/2022]
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50
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