1
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Miao L, Sivak JT, Kotsonis G, Ciston J, Ophus CL, Dabo I, Maria JP, Sinnott SB, Alem N. Chemical Environment and Structural Variations in High Entropy Oxide Thin Film Probed with Electron Microscopy. ACS NANO 2024; 18:14968-14977. [PMID: 38818542 DOI: 10.1021/acsnano.4c00787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
We employ analytical transmission electron microscopy (TEM) to correlate the structural and chemical environment variations within a stacked epitaxial thin film of the high entropy oxide (HEO) Mg0.2Co0.2Ni0.2Cu0.2Zn0.2O (J14), with two layers grown at different substrate temperatures (500 and 200 °C) using pulsed laser deposition (PLD). Electron diffraction and atomically resolved STEM imaging reveal the difference in out-of-plane lattice parameters in the stacked thin film, which is further quantified on a larger scale using four-dimensional STEM (4D-STEM). In the layer deposited at a lower temperature, electron energy loss spectroscopy (EELS) mapping indicates drastic changes in the oxidation states and bonding environment for Co ions, and energy-dispersive X-ray spectroscopy (EDX) mapping detects more significant cation deficiency. Ab initio density functional theory (DFT) calculations validate that vacancies on the cation sublattice of J14 result in significant electronic and structural changes. The experimental and computational analyses indicate that low temperatures during film growth result in cation deficiency, an altered chemical environment, and reduced lattice parameters while maintaining a single phase. Our results demonstrate that the complex correlation of configurational entropy, kinetics, and thermodynamics can be utilized for accessing a range of metastable configurations in HEO materials without altering cation proportions, enabling further engineering of functional properties of HEO materials.
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Affiliation(s)
- Leixin Miao
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jacob T Sivak
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - George Kotsonis
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jim Ciston
- National Center for Electron Microscopy Facility, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Colin L Ophus
- National Center for Electron Microscopy Facility, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ismaila Dabo
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jon-Paul Maria
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Susan B Sinnott
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nasim Alem
- Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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2
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Chatzigeorgiou M, Constantoudis V, Katsiotis M, Beazi-Katsioti M, Boukos N. Segmentability evaluation of back-scattered SEM images of multiphase materials. Ultramicroscopy 2024; 257:113892. [PMID: 38065012 DOI: 10.1016/j.ultramic.2023.113892] [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: 07/14/2022] [Revised: 08/22/2023] [Accepted: 11/23/2023] [Indexed: 01/05/2024]
Abstract
Segmentation methods are very useful tools in the Electron Microscopy inspection of materials, enabling the extraction of quantitative results from microscopy images. Back-Scattered Electron (BSE) images carry information of the mean atomic number in the interaction volume and hence can be used to quantify the phase composition in multiphase materials. Since phase composition and proportion affects the material properties and hence its applications, the segmentation accuracy of such images rendered of critical importance for material science. In this work, the notion of segmentability for BSE images is proposed to define the ability of an image to be segmented accurately. This notion can be used to guide the image acquisition process so that segmentability is maximized and segmentation accuracy is ensured. An index is devised to quantify segmentability based on a combination of the modified Fisher Discrimination Ratio and of the second Minkowski functional capturing intensity and spatial aspects of BSE images respectively. The suggested Segmentability Index (SI) is validated in synthetic BSE images which are generated with a novel algorithm allowing the independent control of spatial distribution of phases and their grayscale intensity histograms. Additionally, SI is applied in real-synthetic BSE images, where the real greyscale distributions of Ordinary Portland Cement (OPC) clinker crystallographic phases are used, to demonstrate the ability of SI to indicate the optimum choice of critical image acquisition settings leading to the more accurate segmentation output.
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Affiliation(s)
- Manolis Chatzigeorgiou
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research "Demokritos", Patriarchou Grigoriou E' & Neapoleos Str., Agia Paraskevi Attikis, Greece; School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens, Zografou 15780, Greece.
| | - Vassilios Constantoudis
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research "Demokritos", Patriarchou Grigoriou E' & Neapoleos Str., Agia Paraskevi Attikis, Greece
| | - Marios Katsiotis
- Group Innovation & Technology, TITAN Cement S.A., 22A Halkidos Street, Athens 111 43, Greece
| | - Margarita Beazi-Katsioti
- School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Street, Athens, Zografou 15780, Greece
| | - Nikos Boukos
- Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research "Demokritos", Patriarchou Grigoriou E' & Neapoleos Str., Agia Paraskevi Attikis, Greece
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3
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Vollmer C, Kepaptsoglou D, Leitner J, Mosberg AB, El Hajraoui K, King AJ, Bays CL, Schofield PF, Araki T, Ramasse QM. High-spatial resolution functional chemistry of nitrogen compounds in the observed UK meteorite fall Winchcombe. Nat Commun 2024; 15:778. [PMID: 38278803 PMCID: PMC10817942 DOI: 10.1038/s41467-024-45064-x] [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: 07/13/2023] [Accepted: 01/11/2024] [Indexed: 01/28/2024] Open
Abstract
Organic matter in extraterrestrial samples is a complex material that might have played an important role in the delivery of prebiotic molecules to the early Earth. We report here on the identification of nitrogen-containing compounds such as amino acids and N-heterocycles within the recent observed meteorite fall Winchcombe by high-spatial resolution spectroscopy techniques. Although nitrogen contents of Winchcombe organic matter are low (N/C ~ 1-3%), we were able to detect the presence of these compounds using a low-noise direct electron detector. These biologically relevant molecules have therefore been tentatively found within a fresh, minimally processed meteorite sample by high spatial resolution techniques conserving the overall petrographic context. Carbon functional chemistry investigations show that sizes of aromatic domains are small and that abundances of carboxylic functional groups are low. Our observations demonstrate that Winchcombe represents an important addition to the collection of carbonaceous chondrites and still preserves pristine extraterrestrial organic matter.
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Affiliation(s)
| | - Demie Kepaptsoglou
- SuperSTEM Laboratory, Keckwick Lane, Daresbury, UK
- School of Physics, Engineering and Technology, University of York, Heslington, UK
| | - Jan Leitner
- Institut für Geowissenschaften, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
- Max Planck Institute for Chemistry, Particle Chemistry Department, Mainz, Germany
| | | | - Khalil El Hajraoui
- SuperSTEM Laboratory, Keckwick Lane, Daresbury, UK
- School of Physics, Engineering and Technology, University of York, Heslington, UK
| | - Ashley J King
- Planetary Materials Group, Natural History Museum, London, UK
| | - Charlotte L Bays
- Planetary Materials Group, Natural History Museum, London, UK
- Department of Earth Sciences, Royal Holloway, University of London, Egham, UK
| | | | - Tohru Araki
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK
- National Institutes of Natural Sciences, Institute for Molecular Science, UVSOR Synchrotron Facility, Okazaki, Japan
| | - Quentin M Ramasse
- SuperSTEM Laboratory, Keckwick Lane, Daresbury, UK
- School of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, Leeds, UK
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4
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Yang C, Pons R, Sigle W, Wang H, Benckiser E, Logvenov G, Keimer B, van Aken PA. Direct observation of strong surface reconstruction in partially reduced nickelate films. Nat Commun 2024; 15:378. [PMID: 38191551 PMCID: PMC10774438 DOI: 10.1038/s41467-023-44616-x] [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: 08/15/2023] [Accepted: 12/22/2023] [Indexed: 01/10/2024] Open
Abstract
The polarity of a surface can affect the electronic and structural properties of oxide thin films through electrostatic effects. Understanding the mechanism behind these effects requires knowledge of the atomic structure and electrostatic characteristics at the surface. In this study, we use annular bright-field imaging to investigate the surface structure of a Pr0.8Sr0.2NiO2+x (0 < x < 1) film. We observe a polar distortion coupled with octahedral rotations in a fully oxidized Pr0.8Sr0.2NiO3 sample, and a stronger polar distortion in a partially reduced sample. Its spatial depth extent is about three unit cells from the surface. Additionally, we use four-dimensional scanning transmission electron microscopy (4D-STEM) to directly image the local atomic electric field surrounding Ni atoms near the surface and discover distinct valence variations of Ni atoms, which are confirmed by atomic-resolution electron energy-loss spectroscopy (EELS). Our results suggest that the strong surface reconstruction in the reduced sample is closely related to the formation of oxygen vacancies from topochemical reduction. These findings provide insights into the understanding and evolution of surface polarity at the atomic level.
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Affiliation(s)
- Chao Yang
- Max Planck Institute for Solid State Research, Stuttgart, Germany.
| | - Rebecca Pons
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Wilfried Sigle
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Hongguang Wang
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Eva Benckiser
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Gennady Logvenov
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Bernhard Keimer
- Max Planck Institute for Solid State Research, Stuttgart, Germany
| | - Peter A van Aken
- Max Planck Institute for Solid State Research, Stuttgart, Germany
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5
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Dursap T, Fadel M, Regreny P, Tapia Garcia C, Chevalier C, Nguyen HS, Drouard E, Brottet S, Gendry M, Danescu A, Koepf M, Artero V, Bugnet M, Penuelas J. Enhanced Light Trapping in GaAs/TiO 2-Based Photocathodes for Hydrogen Production. ACS APPLIED MATERIALS & INTERFACES 2023; 15:53446-53454. [PMID: 37943978 DOI: 10.1021/acsami.3c11481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Photoelectrochemical cells (PEC) are appealing devices for the production of renewable energy carriers. In this context, III-V semiconductors such as GaAs are very promising materials due to their tunable band gaps, which can be appropriately adjusted for sunlight harvesting. Because of the high cost of these semiconductors, the nanostructuring of the photoactive layer can help to improve the device efficiency as well as drastically reduce the amount of material needed. III-V nanowire-based photoelectrodes benefit from the intrinsically high aspect ratio of nanowires, their enhanced ability to trap light, and their improved charge separation and collection abilities and thus are particularly attractive for PECs. However, III-V semiconductors often suffer from corrosion in aqueous electrolytes, preventing their utilization over long periods under relevant working conditions. Here, photocathodes of GaAs nanowires protected with thin TiO2 shells were prepared and studied under simulated sunlight irradiation to assess their photoelectrochemical performances in correlation with their structural degradation, highlighting the advantageous nanowire geometry compared to its thin-film counterpart. Morphological and electronic parameters, such as the aspect ratio of the nanowires and their doping pattern, were found to strongly influence the photocatalytic performances of the system. This work highlights the advantageous combination of nanowires featuring a buried radial p-n junction with Co nanoparticles used as a hydrogen evolution catalyst. The nanostructured photocathodes exhibit significant photocatalytic activities comparable with previous noble-metal-based systems. This study demonstrates the potential of a GaAs nanostructured semiconductor and its reliable use for photodriven hydrogen production.
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Affiliation(s)
- Thomas Dursap
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Mariam Fadel
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 38000 Grenoble, France
| | - Philippe Regreny
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Cristina Tapia Garcia
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 38000 Grenoble, France
| | - Céline Chevalier
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Hai Son Nguyen
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Emmanuel Drouard
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Solène Brottet
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Michel Gendry
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Alexandru Danescu
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
| | - Matthieu Koepf
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 38000 Grenoble, France
| | - Vincent Artero
- Univ. Grenoble Alpes, CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux, 38000 Grenoble, France
| | - Matthieu Bugnet
- Univ. Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR 5510, 69621 Villeurbanne, France
| | - José Penuelas
- Univ. Lyon, CNRS, ECL, INSA Lyon, UCBL, CPE Lyon, INL, UMR 5270, 69130 Ecully, France
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6
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Laurita A, Zhu L, Cabelguen PE, Auvergniot J, Hamon J, Guyomard D, Dupré N, Moreau P. Pristine Surface of Ni-Rich Layered Transition Metal Oxides as a Premise of Surface Reactivity. ACS APPLIED MATERIALS & INTERFACES 2022; 14:41945-41956. [PMID: 36094373 DOI: 10.1021/acsami.2c09358] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The surface reactivity of Ni-rich layered transition metal oxides is instrumental to the performance of batteries based on these positive electrode materials. Most often, strong surface modifications are detailed with respect to a supposed ideal initial state. Here, we study the LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode material in its pristine state, hence before any contact with electrolyte or cycling, thanks to advanced microscopy and spectroscopy techniques to fully characterize its surface down to the nanometer scale. Scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS), solid-state nuclear magnetic resonance (SS-NMR), and X-ray photoelectron spectroscopy (XPS) are combined and correlated in an innovative manner. The results demonstrate that in usual storage conditions after synthesis, the extreme surface is already chemically different from the nominal values. In particular, nickel is found in a reduced state compared to the bulk value, and a Mn enrichment is determined in the first few nanometers of primary particles. Further exposition to humid air allows for quantifying the formed lithiated species per gram of active material, identifying their repartition and proposing a reaction path in relation with the instability of the surface.
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Affiliation(s)
- Angelica Laurita
- Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel (IMN), F-44000 Nantes, France
| | - Liang Zhu
- Umicore, 31 rue du Marais, Brussels BE-1000, Belgium
| | | | | | - Jonathan Hamon
- Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel (IMN), F-44000 Nantes, France
| | - Dominique Guyomard
- Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel (IMN), F-44000 Nantes, France
| | - Nicolas Dupré
- Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel (IMN), F-44000 Nantes, France
| | - Philippe Moreau
- Nantes Université, CNRS, Institut des Matériaux de Nantes Jean Rouxel (IMN), F-44000 Nantes, France
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7
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Türk H, Götsch T, Schmidt FP, Hammud A, Ivanov D, de Haart L(B, Vinke I, Eichel RA, Schlögl R, Reuter K, Knop-Gericke A, Lunkenbein T, Scheurer C. Sr Surface Enrichment in Solid Oxide Cells ‐ Approaching the Limits of EDX Analysis by Multivariate Statistical Analysis and Simulations. ChemCatChem 2022. [DOI: 10.1002/cctc.202200300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Hanna Türk
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Theory Department Faradayweg 4-6 14195 Berlin GERMANY
| | - Thomas Götsch
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Department of Inorganic Chemistry GERMANY
| | - Franz-Philipp Schmidt
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Department of Inorganic Chemistry GERMANY
| | - Adnan Hammud
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Department of Inorganic Chemistry GERMANY
| | - Danail Ivanov
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Department of Inorganic Chemistry GERMANY
| | - L.G.J. (Bert) de Haart
- Julich Research Centre Institute of Energy and Climate Research Helmholtz-Institute Münster: Ionics in Energy Storage: Forschungszentrum Julich Helmholtz-Institut Munster Institut fur Energie- und Klimaforschung Elektrochemische Verfahrenstechnik Fundamental Electrochemistry (IEK-9) GERMANY
| | - Izaak Vinke
- Julich Research Centre Institute of Energy and Climate Research Helmholtz-Institute Münster: Ionics in Energy Storage: Forschungszentrum Julich Helmholtz-Institut Munster Institut fur Energie- und Klimaforschung Elektrochemische Verfahrenstechnik Fundamental Electrochemistry (IEK-9) GERMANY
| | - Rüdiger-A Eichel
- Julich Research Centre Institute of Energy and Climate Research Helmholtz-Institute Münster: Ionics in Energy Storage: Forschungszentrum Julich Helmholtz-Institut Munster Institut fur Energie- und Klimaforschung Elektrochemische Verfahrenstechnik Fundamental Electrochemistry (IEK-9) GERMANY
| | - Robert Schlögl
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Department of Inorganic Chemistry GERMANY
| | - Karsten Reuter
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Theory Department GERMANY
| | - Axel Knop-Gericke
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Fundamental Electrochemistry (IEK-9) GERMANY
| | - Thomas Lunkenbein
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Department of Inorganic Chemistry GERMANY
| | - Christoph Scheurer
- Fritz-Haber-Institut der Max-Planck-Gesellschaft Theory Faradayweg 4-6 14195 Berlin GERMANY
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8
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Haselmann U, Radlinger T, Pei W, Popov MN, Spitaler T, Romaner L, Ivanov YP, Chen J, He Y, Kothleitner G, Zhang Z. Ca Solubility in a BiFeO 3-Based System with a Secondary Bi 2O 3 Phase on a Nanoscale. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:7696-7703. [PMID: 35558823 PMCID: PMC9082603 DOI: 10.1021/acs.jpcc.2c00674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/02/2022] [Indexed: 06/15/2023]
Abstract
In BiFeO3 (BFO), Bi2O3 (BO) is a known secondary phase, which can appear under certain growth conditions. However, BO is not just an unwanted parasitic phase but can be used to create the super-tetragonal BFO phase in films on substrates, which would otherwise grow in the regular rhombohedral phase (R-phase). The super-tetragonal BFO phase has the advantage of a much larger ferroelectric polarization of 130-150 μC/cm2, which is around 1.5 times the value of the rhombohedral phase with 80-100 μC/cm2. Here, we report that the solubility of Ca, which is a common dopant of bismuth ferrite materials to tune their properties, is significantly lower in the secondary BO phase than in the observed R-phase BFO. Starting from the film growth, this leads to completely different Ca concentrations in the two phases. We show this with advanced analytical transmission electron microscopy techniques and confirm the experimental results with density functional theory (DFT) calculations. At the film's fabrication temperature, caused by different solubilities, about 50 times higher Ca concentration is expected in the BFO phase than in the secondary one. Depending on the cooling rate after fabrication, this can further increase since a larger Ca concentration difference is expected at lower temperatures. When fabricating functional devices using Ca doping and the secondary BO phase, the difference in solubility must be considered because, depending on the ratio of the BO phase, the Ca concentration in the BFO phase can become much higher than intended. This can be critical for the intended device functionality because the Ca concentration strongly influences and modifies the BFO properties.
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Affiliation(s)
- Ulrich Haselmann
- Erich
Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria
| | - Thomas Radlinger
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria
| | - Weijie Pei
- School
of Materials Science & Engineering, Hubei University, 430062 Wuhan, Hubei, China
| | - Maxim N. Popov
- Materials
Center Leoben Forschung GmbH, 8700 Leoben, Austria
| | - Tobias Spitaler
- Department
of Materials Science, Montanuniversität
Leoben, 8700 Leoben, Austria
| | - Lorenz Romaner
- Materials
Center Leoben Forschung GmbH, 8700 Leoben, Austria
- Department
of Materials Science, Montanuniversität
Leoben, 8700 Leoben, Austria
| | - Yurii P. Ivanov
- Department
of Materials Science & Metallurgy, University
of Cambridge, Cambridge CB3 0FS, U.K.
- School
of Natural Sciences, Far Eastern Federal University, 690950 Vladivostok, Russia
| | - Jian Chen
- School
of Materials Science & Engineering, Hubei University, 430062 Wuhan, Hubei, China
| | - Yunbin He
- School
of Materials Science & Engineering, Hubei University, 430062 Wuhan, Hubei, China
| | - Gerald Kothleitner
- Institute
for Electron Microscopy and Nanoanalysis, Graz University of Technology, 8010 Graz, Austria
- Graz
Centre for Electron Microscopy, Austrian Cooperative Research, 8010 Graz, Austria
| | - Zaoli Zhang
- Erich
Schmid Institute of Materials Science, Austrian Academy of Sciences, 8700 Leoben, Austria
- Institute
of Material Physics, Montanuniversität Leoben, 8700 Leoben, Austria
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9
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Muzzi B, Albino M, Petrecca M, Innocenti C, Fernández CDJ, Bertoni G, Marquina C, Ibarra MR, Sangregorio C. 3d Metal Doping of Core@Shell Wüstite@ferrite Nanoparticles as a Promising Route toward Room Temperature Exchange Bias Magnets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107426. [PMID: 35274450 DOI: 10.1002/smll.202107426] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/21/2022] [Indexed: 06/14/2023]
Abstract
Nanometric core@shell wüstite@ferrite (Fe1-x O@Fe3 O4 ) has been extensively studied because of the emergence of exchange bias phenomena. Since their actual implementation in modern technologies is hampered by the low temperature at which bias is operating, the critical issue to be solved is to obtain exchange-coupled antiferromagnetic@ferrimagnetic nanoparticles (NPs) with ordering temperature close to 300 K by replacing the divalent iron with other transition-metal ions. Here, the effect of the combined substitution of Fe(II) with Co(II) and Ni(II) on the crystal structure and magnetic properties is studied. To this aim, a series of 20 nm NPs with a wüstite-based core and a ferrite shell, with tailored composition, (Co0.3 Fe0.7 O@Co0.8 Fe2.2 O4 and Ni0.17 Co0.21 Fe0.62 O@Ni0.4 Co0.3 Fe2.3 O4 ) is synthetized through a thermal-decomposition method. An extensive morphological and crystallographic characterization of the obtained NPs shows how a higher stability against the oxidation process in ambient condition is attained when divalent cation doping of the iron oxide lattice with Co(II) and Ni(II) ions is performed. The dual-doping is revealed to be an efficient way for tuning the magnetic properties of the final system, obtaining Ni-Co doped iron oxide core@shell NPs with high coercivity (and therefore, high energy product), and increased antiferromagnetic ordering transition temperature, close to room temperature.
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Affiliation(s)
- Beatrice Muzzi
- Departament of Biotechnology, Chemistry and Pharmacy, University of Siena 1240, Siena, I-53100, Italy
- ICCOM - CNR, Sesto Fiorentino FI, I-50019, Italy
- Departament of Chemistry "U. Schiff", University of Florence and INSTM, Sesto Fiorentino FI, I-50019, Italy
| | - Martin Albino
- Departament of Chemistry "U. Schiff", University of Florence and INSTM, Sesto Fiorentino FI, I-50019, Italy
| | - Michele Petrecca
- Departament of Chemistry "U. Schiff", University of Florence and INSTM, Sesto Fiorentino FI, I-50019, Italy
| | - Claudia Innocenti
- ICCOM - CNR, Sesto Fiorentino FI, I-50019, Italy
- Departament of Chemistry "U. Schiff", University of Florence and INSTM, Sesto Fiorentino FI, I-50019, Italy
| | | | | | - Clara Marquina
- Instituto de Nanociencia y Materiales de Aragón (INMA), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Zaragoza, Zaragoza, 50009, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza, 50009, Spain
| | - Manuel Ricardo Ibarra
- Instituto de Nanociencia y Materiales de Aragón (INMA), Consejo Superior de Investigaciones Científicas (CSIC)-Universidad de Zaragoza, Zaragoza, 50009, Spain
- Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza, 50009, Spain
- Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza, Zaragoza, 50018, Spain
| | - Claudio Sangregorio
- ICCOM - CNR, Sesto Fiorentino FI, I-50019, Italy
- Departament of Chemistry "U. Schiff", University of Florence and INSTM, Sesto Fiorentino FI, I-50019, Italy
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10
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Abstract
The NdNiO3 (NNO) system has attracted a considerable amount of attention owing to the discovery of superconductivity in Nd0.8Sr0.2NiO2. In rare-earth nickelates, Ruddlesden–Popper (RP) faults play a significant role in functional properties, motivating our exploration of its microstructural characteristics and the electronic structure. Here, we employed aberration-corrected scanning transmission electron microscopy and spectroscopy to study a NdNiO3 film grown by layer-by-layer molecular beam epitaxy (MBE). We found RP faults with multiple configurations in high-angle annular dark-field images. Elemental intermixing occurs at the SrTiO3–NdNiO3 interface and in the RP fault regions. Quantitative analysis of the variation in lattice constants indicates that large strains exist around the substrate–film interface. We demonstrate that the Ni valence change around RP faults is related to a strain and structure variation. This work provides insights into the microstructure and electronic-structure modifications around RP faults in nickelates.
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11
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Cao P, Tang P, Bekheet MF, Du H, Yang L, Haug L, Gili A, Bischoff B, Gurlo A, Kunz M, Dunin-Borkowski RE, Penner S, Heggen M. Atomic-Scale Insights into Nickel Exsolution on LaNiO 3 Catalysts via In Situ Electron Microscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2022; 126:786-796. [PMID: 35059098 PMCID: PMC8762657 DOI: 10.1021/acs.jpcc.1c09257] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/16/2021] [Indexed: 06/14/2023]
Abstract
Using a combination of in situ bulk and surface characterization techniques, we provide atomic-scale insight into the complex surface and bulk dynamics of a LaNiO3 perovskite material during heating in vacuo. Driven by the outstanding activity LaNiO3 in the methane dry reforming reaction (DRM), attributable to the decomposition of LaNiO3 during DRM operation into a Ni//La2O3 composite, we reveal the Ni exsolution dynamics both on a local and global scale by in situ electron microscopy, in situ X-ray diffraction and in situ X-ray photoelectron spectroscopy. To reduce the complexity and disentangle thermal from self-activation and reaction-induced effects, we embarked on a heating experiment in vacuo under comparable experimental conditions in all methods. Associated with the Ni exsolution, the remaining perovskite grains suffer a drastic shrinkage of the grain volume and compression of the structure. Ni particles mainly evolve at grain boundaries and stacking faults. Sophisticated structure analysis of the elemental composition by electron-energy loss mapping allows us to disentangle the distribution of the different structures resulting from LaNiO3 decomposition on a local scale. Important for explaining the DRM activity, our results indicate that most of the Ni moieties are oxidized and that the formation of NiO occurs preferentially at grain edges, resulting from the reaction of the exsolved Ni particles with oxygen released from the perovskite lattice during decomposition via a spillover process from the perovskite to the Ni particles. Correlating electron microscopy and X-ray diffraction data allows us to establish a sequential two-step process in the decomposition of LaNiO3 via a Ruddlesden-Popper La2NiO4 intermediate structure. Exemplified for the archetypical LaNiO3 perovskite material, our results underscore the importance of focusing on both surface and bulk characterization for a thorough understanding of the catalyst dynamics and set the stage for a generalized concept in the understanding of state-of-the art catalyst materials on an atomic level.
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Affiliation(s)
- Pengfei Cao
- School of Chemical
Engineering and Technology, Xi’an
Jiaotong University, Xi’an 710049, China
- Ernst Ruska-Centre
for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
| | - Pengyi Tang
- Ernst Ruska-Centre
for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
- State Key Laboratory
of Information Functional Materials, 2020 X-Lab, ShangHai Institute
of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Maged F. Bekheet
- Chair of Advanced
Ceramic Materials, Institut für Werkstoffwissenschaften und
-technologien, Technical University Berlin, Hardenbergstrasse 40, D-10623 Berlin, Germany
| | - Hongchu Du
- Ernst Ruska-Centre
for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
| | - Luyan Yang
- Ernst Ruska-Centre
for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
| | - Leander Haug
- Department of Physical Chemistry, University
of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria
| | - Albert Gili
- Chair of Advanced
Ceramic Materials, Institut für Werkstoffwissenschaften und
-technologien, Technical University Berlin, Hardenbergstrasse 40, D-10623 Berlin, Germany
| | - Benjamin Bischoff
- Chair of Advanced
Ceramic Materials, Institut für Werkstoffwissenschaften und
-technologien, Technical University Berlin, Hardenbergstrasse 40, D-10623 Berlin, Germany
| | - Aleksander Gurlo
- Chair of Advanced
Ceramic Materials, Institut für Werkstoffwissenschaften und
-technologien, Technical University Berlin, Hardenbergstrasse 40, D-10623 Berlin, Germany
| | - Martin Kunz
- Advanced Light Source, Lawrence
Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Rafal E. Dunin-Borkowski
- Ernst Ruska-Centre
for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
| | - Simon Penner
- Department of Physical Chemistry, University
of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria
| | - Marc Heggen
- Ernst Ruska-Centre
for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, Leo-Brandt-Strasse 1, D-52428 Jülich, Germany
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12
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Yang C, Wang Y, Sigle W, van Aken PA. Determination of Grain-Boundary Structure and Electrostatic Characteristics in a SrTiO 3 Bicrystal by Four-Dimensional Electron Microscopy. NANO LETTERS 2021; 21:9138-9145. [PMID: 34672612 PMCID: PMC8587898 DOI: 10.1021/acs.nanolett.1c02960] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The grain boundary (GB) plays a critical role in a material's properties and device performance. Therefore, the characterization of a GB's atomic structure and electrostatic characteristics is a matter of great importance for materials science. Here, we report on the atomic structure and electrostatic analysis of a GB in a SrTiO3 bicrystal by four-dimensional scanning transmission electron microscopy (4D-STEM). We demonstrate that the Σ5 GB is Ti-rich and poor in Sr. We investigate possible effects on the variation in the atomic electrostatic field, including oxygen vacancies, Ti-valence change, and accumulation of cations. A negative charge resulting from a space-charge zone in SrTiO3 compensates a positive charge accumulated at the GB, which is in agreement with the double-Schottky-barrier model. It demonstrates the feasibility of characterizing the electrostatic properties at the nanometer scale by 4D-STEM, which provides comprehensive insights to understanding the GB structure and its concomitant effects on the electrostatic properties.
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Affiliation(s)
- Chao Yang
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - Yi Wang
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
- Center
for Microscopy and Analysis, Nanjing University
of Aeronautics and Astronautics, Nanjing 210016, P.R. China
| | - Wilfried Sigle
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
| | - Peter A. van Aken
- Max
Planck Institute for Solid State Research, Stuttgart 70569, Germany
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13
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Caleffi M, Mariani P, Bertoni G, Paolicelli G, Pasquali L, Agresti A, Pescetelli S, Di Carlo A, De Renzi V, D’Addato S. Ag/MgO Nanoparticles via Gas Aggregation Nanocluster Source for Perovskite Solar Cell Engineering. MATERIALS 2021; 14:ma14195507. [PMID: 34639901 PMCID: PMC8509757 DOI: 10.3390/ma14195507] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/18/2021] [Accepted: 09/21/2021] [Indexed: 11/25/2022]
Abstract
Nanocluster aggregation sources based on magnetron-sputtering represent precise and versatile means to deposit a controlled quantity of metal nanoparticles at selected interfaces. In this work, we exploit this methodology to produce Ag/MgO nanoparticles (NPs) and deposit them on a glass/FTO/TiO2 substrate, which constitutes the mesoscopic front electrode of a monolithic perovskite-based solar cell (PSC). Herein, the Ag NP growth through magnetron sputtering and gas aggregation, subsequently covered with MgO ultrathin layers, is fully characterized in terms of structural and morphological properties while thermal stability and endurance against air-induced oxidation are demonstrated in accordance with PSC manufacturing processes. Finally, once the NP coverage is optimized, the Ag/MgO engineered PSCs demonstrate an overall increase of 5% in terms of device power conversion efficiencies (up to 17.8%).
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Affiliation(s)
- Matteo Caleffi
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Università di Modena e Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy; (V.D.R.); (S.D.)
- Correspondence: (M.C.); (A.A.)
| | - Paolo Mariani
- CHOSE—Centre for Hybrid and Organic Solar Energy, Department of Electronics Engineering, University of Rome Tor Vergata, 00133 Rome, Italy; (P.M.); (S.P.); (A.D.C.)
| | - Giovanni Bertoni
- CNR—Consiglio Nazionale delle Ricerche, Istituto Nanoscienze, Via Campi 213/A, 41125 Modena, Italy; (G.B.); (G.P.)
- IMEM—CNR, Istituto dei Materiali per l’Elettronica ed il Magnetismo, Consiglio Nazionale delle Ricerche, Parco Area delle Scienze 37/A, 43124 Parma, Italy
| | - Guido Paolicelli
- CNR—Consiglio Nazionale delle Ricerche, Istituto Nanoscienze, Via Campi 213/A, 41125 Modena, Italy; (G.B.); (G.P.)
| | - Luca Pasquali
- Dipartimento di Ingegneria E. Ferrari, Università di Modena e Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy;
- IOM—CNR, Istituto Officina dei Materiali, Consiglio Nazionale delle Ricerche, s.s. 14, Km. 163.5 in AREA Science Park, Basovizza, 34149 Trieste, Italy
- Department of Physics, University of Johannesburg, P.O. Box 524, Auckland Park 2006, South Africa
| | - Antonio Agresti
- CHOSE—Centre for Hybrid and Organic Solar Energy, Department of Electronics Engineering, University of Rome Tor Vergata, 00133 Rome, Italy; (P.M.); (S.P.); (A.D.C.)
- Correspondence: (M.C.); (A.A.)
| | - Sara Pescetelli
- CHOSE—Centre for Hybrid and Organic Solar Energy, Department of Electronics Engineering, University of Rome Tor Vergata, 00133 Rome, Italy; (P.M.); (S.P.); (A.D.C.)
| | - Aldo Di Carlo
- CHOSE—Centre for Hybrid and Organic Solar Energy, Department of Electronics Engineering, University of Rome Tor Vergata, 00133 Rome, Italy; (P.M.); (S.P.); (A.D.C.)
- ISM—CNR, Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, 00133 Rome, Italy
| | - Valentina De Renzi
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Università di Modena e Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy; (V.D.R.); (S.D.)
- CNR—Consiglio Nazionale delle Ricerche, Istituto Nanoscienze, Via Campi 213/A, 41125 Modena, Italy; (G.B.); (G.P.)
| | - Sergio D’Addato
- Dipartimento di Scienze Fisiche, Matematiche e Informatiche, Università di Modena e Reggio Emilia, Via Campi 213/A, 41125 Modena, Italy; (V.D.R.); (S.D.)
- CNR—Consiglio Nazionale delle Ricerche, Istituto Nanoscienze, Via Campi 213/A, 41125 Modena, Italy; (G.B.); (G.P.)
- EN & TECH, Università di Modena e Reggio Emilia, 41125 Modena, Italy
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14
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Extraction of physically meaningful endmembers from STEM spectrum-images combining geometrical and statistical approaches. Micron 2021; 145:103068. [PMID: 33892400 DOI: 10.1016/j.micron.2021.103068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 04/01/2021] [Accepted: 04/01/2021] [Indexed: 11/20/2022]
Abstract
This article addresses extraction of physically meaningful information from STEM EELS and EDX spectrum-images using methods of Multivariate Statistical Analysis. The problem is interpreted in terms of data distribution in a multi-dimensional factor space, which allows for a straightforward and intuitively clear comparison of various approaches. A new computationally efficient and robust method for finding physically meaningful endmembers in spectrum-image datasets is presented. The method combines the geometrical approach of Vertex Component Analysis with the statistical approach of Bayesian inference. The algorithm is described in detail at an example of EELS spectrum-imaging of a multi-compound CMOS transistor.
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15
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Wind L, Sistani M, Song Z, Maeder X, Pohl D, Michler J, Rellinghaus B, Weber WM, Lugstein A. Monolithic Metal-Semiconductor-Metal Heterostructures Enabling Next-Generation Germanium Nanodevices. ACS APPLIED MATERIALS & INTERFACES 2021; 13:12393-12399. [PMID: 33683092 PMCID: PMC7975277 DOI: 10.1021/acsami.1c00502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Low-dimensional Ge is perceived as a promising building block for emerging optoelectronic devices. Here, we present a wafer-scale platform technology enabling monolithic Al-Ge-Al nanostructures fabricated by a thermally induced Al-Ge exchange reaction. Transmission electron microscopy confirmed the purity and crystallinity of the formed Al segments with an abrupt interface to the remaining Ge segment. In good agreement with the theoretical value of bulk Al-Ge Schottky junctions, a barrier height of 200 ± 20 meV was determined. Photoluminescence and μ-Raman measurements proved the optical quality of the Ge channel embedded in the monolithic Al-Ge-Al heterostructure. Together with the wafer-scale accessibility, the proposed fabrication scheme may give rise to the development of key components of a broad spectrum of emerging Ge-based devices requiring monolithic metal-semiconductor-metal heterostructures with high-quality interfaces.
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Affiliation(s)
- Lukas Wind
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Masiar Sistani
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Zehao Song
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Xavier Maeder
- Swiss
Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Darius Pohl
- Dresden
Center for Nanoanalysis, Technische Universität
Dresden, Helmholtzstraße
18, Dresden 01069, Germany
| | - Johann Michler
- Swiss
Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, Thun 3602, Switzerland
| | - Bernd Rellinghaus
- Dresden
Center for Nanoanalysis, Technische Universität
Dresden, Helmholtzstraße
18, Dresden 01069, Germany
| | - Walter M. Weber
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
| | - Alois Lugstein
- Institute
of Solid State Electronics, Technische Universität
Wien, Gußhausstraße 25-25a, Vienna 1040, Austria
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16
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Pécz B, Nicotra G, Giannazzo F, Yakimova R, Koos A, Kakanakova-Georgieva A. Indium Nitride at the 2D Limit. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006660. [PMID: 33225494 DOI: 10.1002/adma.202006660] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/01/2020] [Indexed: 06/11/2023]
Abstract
The properties of 2D InN are predicted to substantially differ from the bulk crystal. The predicted appealing properties relate to strong in- and out-of-plane excitons, high electron mobility, efficient strain engineering of their electronic and optical properties, and strong application potential in gas sensing. Until now, the realization of 2D InN remained elusive. In this work, the formation of 2D InN and measurements of its bandgap are reported. Bilayer InN is formed between graphene and SiC by an intercalation process in metal-organic chemical vapor deposition (MOCVD). The thickness uniformity of the intercalated structure is investigated by conductive atomic force microscopy (C-AFM) and the structural properties by atomic resolution transmission electron microscopy (TEM). The coverage of the SiC surface is very high, above 90%, and a major part of the intercalated structure is represented by two sub-layers of indium (In) bonded to nitrogen (N). Scanning tunneling spectroscopy (STS) measurements give a bandgap value of 2 ± 0.1 eV for the 2D InN. The stabilization of 2D InN with a pragmatic wide bandgap and high lateral uniformity of intercalation is demonstrated.
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Affiliation(s)
- Béla Pécz
- Centre for Energy Research, Institute for Technical Physics and Materials Science, Konkoly-Thege M. út 29-33, Budapest, 1121, Hungary
| | - Giuseppe Nicotra
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi, Strada VIII, n. 5, Zona Industriale, Catania, I-95121, Italy
| | - Filippo Giannazzo
- Consiglio Nazionale delle Ricerche, Istituto per la Microelettronica e Microsistemi, Strada VIII, n. 5, Zona Industriale, Catania, I-95121, Italy
| | - Rositsa Yakimova
- Department of Physics, Chemistry and Biology (IFM), Linköping University, Linköping, 581 83, Sweden
| | - Antal Koos
- Centre for Energy Research, Institute for Technical Physics and Materials Science, Konkoly-Thege M. út 29-33, Budapest, 1121, Hungary
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17
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Abstract
Formation of highly symmetric skeletal elements in demosponges, called spicules, follows a unique biomineralization mechanism in which polycondensation of an inherently disordered amorphous silica is guided by a highly ordered proteinaceous scaffold, the axial filament. The enzymatically active proteins, silicateins, are assembled into a slender hybrid silica/protein crystalline superstructure that directs the morphogenesis of the spicules. Furthermore, silicateins are known to catalyze the formation of a large variety of other technologically relevant organic and inorganic materials. However, despite the biological and biotechnological importance of this macromolecule, its tertiary structure was never determined. Here we report the atomic structure of silicatein and the entire mineral/organic hybrid assembly with a resolution of 2.4 Å. In this work, the serial X-ray crystallography method was successfully adopted to probe the 2-µm-thick filaments in situ, being embedded inside the skeletal elements. In combination with imaging and chemical analysis using high-resolution transmission electron microscopy, we provide detailed information on the enzymatic activity of silicatein, its crystallization, and the emergence of a functional three-dimensional silica/protein superstructure in vivo. Ultimately, we describe a naturally occurring mineral/protein crystalline assembly at atomic resolution.
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18
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Domínguez C, Georgescu AB, Mundet B, Zhang Y, Fowlie J, Mercy A, Waelchli A, Catalano S, Alexander DTL, Ghosez P, Georges A, Millis AJ, Gibert M, Triscone JM. Length scales of interfacial coupling between metal and insulator phases in oxides. NATURE MATERIALS 2020; 19:1182-1187. [PMID: 32778815 DOI: 10.1038/s41563-020-0757-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Controlling phase transitions in transition metal oxides remains a central feature of both technological and fundamental scientific relevance. A well-known example is the metal-insulator transition, which has been shown to be highly controllable. However, the length scale over which these phases can be established is not yet well understood. To gain insight into this issue, we atomically engineered an artificially phase-separated system through fabricating epitaxial superlattices that consist of SmNiO3 and NdNiO3, two materials that undergo a metal-to-insulator transition at different temperatures. We demonstrate that the length scale of the interfacial coupling between metal and insulator phases is determined by balancing the energy cost of the boundary between a metal and an insulator and the bulk phase energies. Notably, we show that the length scale of this effect exceeds that of the physical coupling of structural motifs, which introduces a new framework for interface-engineering properties at temperatures against the bulk energetics.
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Affiliation(s)
- Claribel Domínguez
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland.
| | | | - Bernat Mundet
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Yajun Zhang
- Theoretical Materials Physics, CESAM, University of Liège, Liège, Belgium
| | - Jennifer Fowlie
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
| | - Alain Mercy
- Theoretical Materials Physics, CESAM, University of Liège, Liège, Belgium
| | - Adrien Waelchli
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
| | - Sara Catalano
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
| | - Duncan T L Alexander
- Electron Spectrometry and Microscopy Laboratory (LSME), Institute of Physics (IPHYS), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Philippe Ghosez
- Theoretical Materials Physics, CESAM, University of Liège, Liège, Belgium
| | - Antoine Georges
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, USA
- Collège de France, Paris, France
- Centre de Physique Théorique (CPHT), CNRS, Institut Polytechnique de Paris, Paris, France
| | - Andrew J Millis
- Center for Computational Quantum Physics, Flatiron Institute, New York, NY, USA
- Department of Physics, Columbia University, New York, NY, USA
| | - Marta Gibert
- Physik-Institut, University of Zurich, Zurich, Switzerland
| | - Jean-Marc Triscone
- Department of Quantum Matter Physics, University of Geneva, Geneva, Switzerland
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19
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Zamani M, Imbalzano G, Tappy N, Alexander DTL, Martí-Sánchez S, Ghisalberti L, Ramasse QM, Friedl M, Tütüncüoglu G, Francaviglia L, Bienvenue S, Hébert C, Arbiol J, Ceriotti M, Fontcuberta I Morral A. 3D Ordering at the Liquid-Solid Polar Interface of Nanowires. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2001030. [PMID: 32762011 DOI: 10.1002/adma.202001030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 06/29/2020] [Indexed: 06/11/2023]
Abstract
The nature of the liquid-solid interface determines the characteristics of a variety of physical phenomena, including catalysis, electrochemistry, lubrication, and crystal growth. Most of the established models for crystal growth are based on macroscopic thermodynamics, neglecting the atomistic nature of the liquid-solid interface. Here, experimental observations and molecular dynamics simulations are employed to identify the 3D nature of an atomic-scale ordering of liquid Ga in contact with solid GaAs in a nanowire growth configuration. An interplay between the liquid ordering and the formation of a new bilayer is revealed, which, contrary to the established theories, suggests that the preference for a certain polarity and polytypism is influenced by the atomic structure of the interface. The conclusions of this work open new avenues for the understanding of crystal growth, as well as other processes and systems involving a liquid-solid interface.
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Affiliation(s)
- Mahdi Zamani
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Giulio Imbalzano
- Laboratory of Computational Science and Modeling, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Nicolas Tappy
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Duncan T L Alexander
- Electron Spectrometry and Microscopy Laboratory, Institute of Physics, Faculty of Basic Sciences, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
- Interdisciplinary Centre for Electron Microscopy (CIME), École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Sara Martí-Sánchez
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, Catalonia, 08193, Spain
| | - Lea Ghisalberti
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury, WA4 4AD, UK
- School of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT, UK
| | - Martin Friedl
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Gözde Tütüncüoglu
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Luca Francaviglia
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Sebastien Bienvenue
- Laboratory of Computational Science and Modeling, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Cécile Hébert
- Electron Spectrometry and Microscopy Laboratory, Institute of Physics, Faculty of Basic Sciences, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
- Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Jordi Arbiol
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, Barcelona, Catalonia, 08193, Spain
- ICREA, Pg. Lluís Companys 23, Barcelona, Catalonia, 08010, Spain
| | - Michele Ceriotti
- Laboratory of Computational Science and Modeling, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
| | - Anna Fontcuberta I Morral
- Laboratory of Semiconductor Materials, Institute of Materials, Faculty of Engineering, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
- Institute of Physics, Faculty of Basic Sciences, École Polytechnique Fédérale de Lausanne, EPFL, Lausanne, 1015, Switzerland
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20
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Heintze C, Formanek P, Pohl D, Hauptstein J, Rellinghaus B, Kröger N. An intimate view into the silica deposition vesicles of diatoms. ACTA ACUST UNITED AC 2020. [DOI: 10.1186/s42833-020-00017-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AbstractDiatoms are single-celled microalgae that produce silica-based cell walls with intricate nano- and micropatterns. Biogenesis of diatom biosilica is a bottom-up process that occurs in large intracellular compartments termed silica deposition vesicles (SDVs). Investigating the mechanisms of silica morphogenesis has so far been severely limited by the lack of methods for imaging the entire volume of an SDV with high spatial resolution during all stages of development. Here we have developed a method that allows for rapid identification and electron microscopy imaging of many different, full sized SDVs that are in the process of producing biosilica valves. This enabled visualizing the development of characteristic morphological biosilica features with unprecedented spatio-temporal resolution. During early to mid-term development, valve SDVs contained ~ 20 nm sized particles that were primarily associated with the radially expanding rib-like biosilica structures. The results from electron dispersive X-ray analysis suggests that the immature biosilica patterns are silica-organic composites. This supports the hypothesis that silica morphogenesis is dependent on organic biomolecules inside the SDV lumen.
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21
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Li S, Li K, Zheng J, Zhang Q, Wei B, Lu X. Structural Distortion-Induced Charge Gradient Distribution of Co Ions in Delithiated LiCoO 2 Cathode. J Phys Chem Lett 2019; 10:7537-7546. [PMID: 31747279 DOI: 10.1021/acs.jpclett.9b02711] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Layered LiCoO2 has drawn tremendous attention as a modeling cathode for Li-ion batteries, while its structural instability, especially in the high delithiation region, remains unsolved. With the aim of revealing the structural fundamentals, LiCoO2 electrodes are investigated at a long delithiation range using both in situ and ex situ techniques. In the highly delithiated LiCoO2 electrode, the unique charge compensation process leads to a spatial charge gradient of Co2+/Co3+/Co4+ ions from surface to bulk, which can be further manipulated by structural distortion, Li extraction, and surface side reactions. The coordinated surface oxygen is shown to be electrochemically active and fully reversible in participating in the charge compensation during cycling. Moreover, the active lattice O can be significantly stabilized by introducing the undesired surface Li-Co antisites, which also play an effective role in accommodating the internal stress induced by volume changes. These findings effectively bridge the structural changes with the Li+/e- migration kinetics to elucidate the degradation of LiCoO2 cathode upon delithiation, demonstrating a rewarding avenue for improving the electrochemical performance of LiCoO2 itself and developing high energy density cathodes for the battery community as well.
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Affiliation(s)
- Shuai Li
- School of Materials , Sun Yat-sen University , Guangzhou 510275 , China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering , Beijing University of Chemical Technology , Beijing 100029 , China
- National Center for Nanoscience and Technology , Beijing 100190 , P.R. China
| | - Kaili Li
- School of Materials , Sun Yat-sen University , Guangzhou 510275 , China
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering , Beijing University of Chemical Technology , Beijing 100029 , China
| | - Jieyun Zheng
- 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
| | - Bin Wei
- School of Materials , Sun Yat-sen University , Guangzhou 510275 , China
| | - Xia Lu
- School of Materials , Sun Yat-sen University , Guangzhou 510275 , China
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22
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Yankovich AB, Munkhbat B, Baranov DG, Cuadra J, Olsén E, Lourenço-Martins H, Tizei LHG, Kociak M, Olsson E, Shegai T. Visualizing Spatial Variations of Plasmon-Exciton Polaritons at the Nanoscale Using Electron Microscopy. NANO LETTERS 2019; 19:8171-8181. [PMID: 31639311 DOI: 10.1021/acs.nanolett.9b03534] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Polaritons are compositional light-matter quasiparticles that have enabled remarkable breakthroughs in quantum and nonlinear optics, as well as in material science. Recently, plasmon-exciton polaritons (plexcitons) have been realized in hybrid material systems composed of transition metal dichalcogenide (TMDC) materials and metal nanoparticles, expanding polaritonic concepts to room temperature and nanoscale systems that also benefit from the exotic properties of TMDC materials. Despite the enormous progress in understanding TMDC-based plexcitons using optical-based methods, experimental evidence of plexcitons formation has remained indirect and mapping their nanometer-scale characteristics has remained an open challenge. Here, we demonstrate that plexcitons generated by a hybrid system composed of an individual silver nanoparticle and a few-layer WS2 flake can be spectroscopically mapped with nanometer spatial resolution using electron energy loss spectroscopy in a scanning transmission electron microscope. Experimental anticrossing measurements using the absorption-dominated extinction signal provide the ultimate evidence for plexciton hybridization in the strong coupling regime. Spatially resolved EELS maps reveal the existence of unexpected nanoscale variations in the deep-subwavelength nature of plexcitons generated by this system. These findings pioneer new possibilities for in-depth studies of the local atomic structure dependence of polariton-related phenomena in TMDC hybrid material systems with nanometer spatial resolution.
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Affiliation(s)
- Andrew B Yankovich
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
| | - Battulga Munkhbat
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
| | - Denis G Baranov
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
| | - Jorge Cuadra
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
| | - Erik Olsén
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
| | - Hugo Lourenço-Martins
- Laboratoire de Physique des Solides , Paris-Sud Université, CNRS UMR 8502 , Orsay , France
| | - Luiz H G Tizei
- Laboratoire de Physique des Solides , Paris-Sud Université, CNRS UMR 8502 , Orsay , France
| | - Mathieu Kociak
- Laboratoire de Physique des Solides , Paris-Sud Université, CNRS UMR 8502 , Orsay , France
| | - Eva Olsson
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
| | - Timur Shegai
- Department of Physics , Chalmers University of Technology , 412 96 , Gothenburg , Sweden
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23
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Ismail ASM, Casavola M, Liu B, Gloter A, van Deelen TW, Versluijs M, Meeldijk JD, Stéphan O, de Jong KP, de Groot FMF. Atomic-Scale Investigation of the Structural and Electronic Properties of Cobalt–Iron Bimetallic Fischer–Tropsch Catalysts. ACS Catal 2019. [DOI: 10.1021/acscatal.8b04334] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ahmed S. M. Ismail
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Marianna Casavola
- Experimental Biophysics and Nanotechnology group, Physics Department, King’s College London, WC2R 2LS London, United Kingdom
| | - Boyang Liu
- Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Alexandre Gloter
- Laboratoire de Physique des Solides, Universitè Paris-Sud, F-91405 Orsay, France
| | - Tom W. van Deelen
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Marjan Versluijs
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Johannes D. Meeldijk
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Odile Stéphan
- Laboratoire de Physique des Solides, Universitè Paris-Sud, F-91405 Orsay, France
| | - Krijn P. de Jong
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Frank M. F. de Groot
- Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CG Utrecht, The Netherlands
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24
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Wilkinson AJ, Collins DM, Zayachuk Y, Korla R, Vilalta-Clemente A. Applications of multivariate statistical methods and simulation libraries to analysis of electron backscatter diffraction and transmission Kikuchi diffraction datasets. Ultramicroscopy 2019; 196:88-98. [DOI: 10.1016/j.ultramic.2018.09.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 09/16/2018] [Accepted: 09/20/2018] [Indexed: 11/28/2022]
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25
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Oberdick SD, Abdelgawad A, Moya C, Mesbahi-Vasey S, Kepaptsoglou D, Lazarov VK, Evans RFL, Meilak D, Skoropata E, van Lierop J, Hunt-Isaak I, Pan H, Ijiri Y, Krycka KL, Borchers JA, Majetich SA. Spin canting across core/shell Fe 3O 4/Mn xFe 3-xO 4 nanoparticles. Sci Rep 2018; 8:3425. [PMID: 29467424 PMCID: PMC5821856 DOI: 10.1038/s41598-018-21626-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/07/2018] [Indexed: 11/21/2022] Open
Abstract
Magnetic nanoparticles (MNPs) have become increasingly important in biomedical applications like magnetic imaging and hyperthermia based cancer treatment. Understanding their magnetic spin configurations is important for optimizing these applications. The measured magnetization of MNPs can be significantly lower than bulk counterparts, often due to canted spins. This has previously been presumed to be a surface effect, where reduced exchange allows spins closest to the nanoparticle surface to deviate locally from collinear structures. We demonstrate that intraparticle effects can induce spin canting throughout a MNP via the Dzyaloshinskii-Moriya interaction (DMI). We study ~7.4 nm diameter, core/shell Fe3O4/MnxFe3−xO4 MNPs with a 0.5 nm Mn-ferrite shell. Mössbauer spectroscopy, x-ray absorption spectroscopy and x-ray magnetic circular dichroism are used to determine chemical structure of core and shell. Polarized small angle neutron scattering shows parallel and perpendicular magnetic correlations, suggesting multiparticle coherent spin canting in an applied field. Atomistic simulations reveal the underlying mechanism of the observed spin canting. These show that strong DMI can lead to magnetic frustration within the shell and cause canting of the net particle moment. These results illuminate how core/shell nanoparticle systems can be engineered for spin canting across the whole of the particle, rather than solely at the surface.
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Affiliation(s)
- Samuel D Oberdick
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Applied Physics Division, Physical Measurement Laboratory, NIST, Boulder, CO, 80305, USA
| | - Ahmed Abdelgawad
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.,Materials Science and Engineering Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Carlos Moya
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | | | - Demie Kepaptsoglou
- SuperSTEM, Sci-Tech Daresbury Campus, Daresbury, WA4 4AD, UK.,Department of Physics, University of York, Heslington, York, YO10 5DD, UK.,The York-JEOL Nanocentre, York Science Park, Heslington, York, YO10 5BR, UK
| | - Vlado K Lazarov
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Richard F L Evans
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Daniel Meilak
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Elizabeth Skoropata
- Physics and Astronomy Department, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Johan van Lierop
- Physics and Astronomy Department, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ian Hunt-Isaak
- Physics and Astronomy Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Hillary Pan
- Physics and Astronomy Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Yumi Ijiri
- Physics and Astronomy Department, Oberlin College, Oberlin, OH, 44074, USA
| | - Kathryn L Krycka
- NIST Center for Neutron Research, NIST, Gaithersburg, Maryland, 20899, USA
| | - Julie A Borchers
- NIST Center for Neutron Research, NIST, Gaithersburg, Maryland, 20899, USA
| | - Sara A Majetich
- Physics Department, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
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26
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Savage AM, Walck SD, Lambeth RH, Beyer FL. Tuning the Morphology of an Acrylate-Based Metallo-Supramolecular Network: From Vesicles to Cylinders. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alice M. Savage
- US Army
Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Scott D. Walck
- US Army
Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Robert H. Lambeth
- US Army
Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
| | - Frederick L. Beyer
- US Army
Research
Laboratory, Aberdeen Proving Ground, Maryland 21005, United States
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27
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Craven AJ, Sala B, Bobynko J, MacLaren I. Spectrum imaging of complex nanostructures using DualEELS: II. Absolute quantification using standards. Ultramicroscopy 2017; 186:66-81. [PMID: 29274506 DOI: 10.1016/j.ultramic.2017.12.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/29/2017] [Accepted: 12/06/2017] [Indexed: 11/29/2022]
Abstract
Nanometre-sized TixV(1-x)CyNz precipitates in an Fe20%Mn steel matrix with a thickness range from 14 to 40 nm are analysed using DualEELS. Their thicknesses, volumes and compositions are quantified using experimental binary standards and the process used to give robust results is described. Precisions of a few percent are achieved with accuracies that are estimated to be of a similar magnitude. Sensitivities are shown to be at 0.5-1 unit cells range in the thinnest matrix region, based on the assumption that a sub-lattice is fully populated by the element. It rises to the 1-2 unit cell range for the metals and 2-3 unit cells for the non-metal in the thickest matrix region. The sensitivities for Ti and N are greater than those for V and C respectively because the O K-edge from surface oxide needs to be separated from the V L2,3-edge, and the C K-edges from C in the matrix and amorphous C on the surface have to be separated from the C in the precipitate itself. Separation of the contributions from the bulk and the surface is demonstrated, showing that there is significant and detectable C in the matrix but no O, while there is significant O but little C in the surface oxide. Whilst applied to precipitates in steel in this work, the approach can be adapted to many multi-phase systems.
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Affiliation(s)
- Alan J Craven
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Bianca Sala
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Joanna Bobynko
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ian MacLaren
- School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
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28
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Kepaptsoglou D, Baran JD, Azough F, Ekren D, Srivastava D, Molinari M, Parker SC, Ramasse QM, Freer R. Prospects for Engineering Thermoelectric Properties in La 1/3NbO 3 Ceramics Revealed via Atomic-Level Characterization and Modeling. Inorg Chem 2017; 57:45-55. [PMID: 29257680 DOI: 10.1021/acs.inorgchem.7b01584] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of experimental and computational techniques has been employed to explore the crystal structure and thermoelectric properties of A-site-deficient perovskite La1/3NbO3 ceramics. Crystallographic data from X-ray and electron diffraction confirmed that the room temperature structure is orthorhombic with Cmmm as a space group. Atomically resolved imaging and analysis showed that there are two distinct A sites: one is occupied with La and vacancies, and the second site is fully unoccupied. The diffuse superstructure reflections observed through diffraction techniques are shown to originate from La vacancy ordering. La1/3NbO3 ceramics sintered in air showed promising high-temperature thermoelectric properties with a high Seebeck coefficient of S1 = -650 to -700 μV/K and a low and temperature-stable thermal conductivity of k = 2-2.2 W/m·K in the temperature range of 300-1000 K. First-principles electronic structure calculations are used to link the temperature dependence of the Seebeck coefficient measured experimentally to the evolution of the density of states with temperature and indicate possible avenues for further optimization through electron doping and control of the A-site occupancies. Moreover, lattice thermal conductivity calculations give insights into the dependence of the thermal conductivity on specific crystallographic directions of the material, which could be exploited via nanostructuring to create high-efficiency compound thermoelectrics.
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Affiliation(s)
| | - Jakub D Baran
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Feridoon Azough
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | - Dursun Ekren
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
| | | | - Marco Molinari
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K.,Department of Chemistry, University of Huddersfield , Huddersfield HD1 3DH, U.K
| | - Stephen C Parker
- Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, U.K
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus , Daresbury WA4 4AD, U.K
| | - Robert Freer
- School of Materials, University of Manchester , Manchester M13 9PL, U.K
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29
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Potapov P, Longo P, Okunishi E. Enhancement of noisy EDX HRSTEM spectrum-images by combination of filtering and PCA. Micron 2017; 96:29-37. [DOI: 10.1016/j.micron.2017.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 12/01/2022]
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30
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Yankovich AB, Verre R, Olsén E, Persson AEO, Trinh V, Dovner G, Käll M, Olsson E. Multidimensional Hybridization of Dark Surface Plasmons. ACS NANO 2017; 11:4265-4274. [PMID: 28350962 DOI: 10.1021/acsnano.7b01318] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Synthetic three-dimensional (3D) nanoarchitectures are providing more control over light-matter interactions and rapidly progressing photonic-based technology. These applications often utilize the strong synergy between electromagnetic fields and surface plasmons (SPs) in metallic nanostructures. However, many of the SP interactions hosted by complex 3D nanostructures are poorly understood because they involve dark hybridized states that are typically undetectable with far-field optical spectroscopy. Here, we use experimental and theoretical electron energy loss spectroscopy to elucidate dark SPs and their interactions in layered metal-insulator-metal disc nanostructures. We go beyond the established dipole SP hybridization analysis by measuring breathing and multipolar SP hybridization. In addition, we reveal multidimensional SP hybridization that simultaneously utilizes in-plane and out-of-plane SP coupling. Near-field classic electrodynamics calculations provide excellent agreement with all experiments. These results advance the fundamental understanding of SP hybridization in 3D nanostructures and provide avenues to further tune the interaction between electromagnetic fields and matter.
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Affiliation(s)
- Andrew B Yankovich
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Ruggero Verre
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Erik Olsén
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Anton E O Persson
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Viet Trinh
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Gudrun Dovner
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Mikael Käll
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
| | - Eva Olsson
- Department of Physics, Chalmers University of Technology , 41296 Gothenburg, Sweden
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31
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Nedelkoski Z, Kepaptsoglou D, Lari L, Wen T, Booth RA, Oberdick SD, Galindo PL, Ramasse QM, Evans RFL, Majetich S, Lazarov VK. Origin of reduced magnetization and domain formation in small magnetite nanoparticles. Sci Rep 2017; 7:45997. [PMID: 28393876 PMCID: PMC5385549 DOI: 10.1038/srep45997] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/07/2017] [Indexed: 11/09/2022] Open
Abstract
The structural, chemical, and magnetic properties of magnetite nanoparticles are compared. Aberration corrected scanning transmission electron microscopy reveals the prevalence of antiphase boundaries in nanoparticles that have significantly reduced magnetization, relative to the bulk. Atomistic magnetic modelling of nanoparticles with and without these defects reveals the origin of the reduced moment. Strong antiferromagnetic interactions across antiphase boundaries support multiple magnetic domains even in particles as small as 12-14 nm.
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Affiliation(s)
- Zlatko Nedelkoski
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | | | - Leonardo Lari
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
| | - Tianlong Wen
- Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, China
| | - Ryan A. Booth
- Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Samuel D. Oberdick
- Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Pedro L. Galindo
- Department of Computer Science and Engineering, Universidad de Cádiz, 11510 Puerto Real, Spain
| | | | | | - Sara Majetich
- Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Vlado K. Lazarov
- Department of Physics, University of York, Heslington, York, YO10 5DD, UK
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32
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Zhong Z, Goris B, Schoenmakers R, Bals S, Batenburg KJ. A bimodal tomographic reconstruction technique combining EDS-STEM and HAADF-STEM. Ultramicroscopy 2017; 174:35-45. [DOI: 10.1016/j.ultramic.2016.12.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/11/2016] [Accepted: 12/08/2016] [Indexed: 11/17/2022]
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33
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Boniface M, Quazuguel L, Danet J, Guyomard D, Moreau P, Bayle-Guillemaud P. Nanoscale Chemical Evolution of Silicon Negative Electrodes Characterized by Low-Loss STEM-EELS. NANO LETTERS 2016; 16:7381-7388. [PMID: 27960471 DOI: 10.1021/acs.nanolett.6b02883] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Continuous solid electrolyte interface (SEI) formation remains the limiting factor of the lifetime of silicon nanoparticles (SiNPs) based negative electrodes. Methods that could provide clear diagnosis of the electrode degradation are of utmost necessity to streamline further developments. We demonstrate that electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM can be used to quickly map SEI components and quantify LixSi alloys from single experiments with resolutions down to 5 nm. Exploiting the low-loss part of the EEL spectrum allowed us to circumvent the degradation phenomena that have so far crippled the application of this technique on such beam-sensitive compounds. Our results provide unprecedented insight into silicon aging mechanisms in full cell configuration. We observe the morphology of the SEI to be extremely heterogeneous at the particle scale but with clear chemical evolutions with extended cycling coming from both SEI accumulation and a transition from lithium-rich carbonate-like compounds to lithium-poor ones. Thanks to the retrieval of several results from a single data set we were able to correlate local discrepancies in lithiation to the initial crystallinity of silicon as well as to the local SEI chemistry and morphology. This study emphasizes how initial heterogeneities in the percolating electronic network and the porosity affect SiNPs aggregates along cycling. These findings pinpoint the crucial role of an optimized formulation in silicon-based thick electrodes.
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Affiliation(s)
- Maxime Boniface
- Université Grenoble Alpes , F-38054 Grenoble, France
- CEA-INAC-MEM , F-38054 Grenoble, France
| | - Lucille Quazuguel
- Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS , 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
| | - Julien Danet
- Université Grenoble Alpes , F-38054 Grenoble, France
- CEA-INAC-MEM , F-38054 Grenoble, France
| | - Dominique Guyomard
- Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS , 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
| | - Philippe Moreau
- Institut des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS , 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
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34
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Realisation of magnetically and atomically abrupt half-metal/semiconductor interface: Co 2FeSi 0.5Al 0.5/Ge(111). Sci Rep 2016; 6:37282. [PMID: 27869132 PMCID: PMC5116668 DOI: 10.1038/srep37282] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/26/2016] [Indexed: 11/08/2022] Open
Abstract
Halfmetal-semiconductor interfaces are crucial for hybrid spintronic devices. Atomically sharp interfaces with high spin polarisation are required for efficient spin injection. In this work we show that thin film of half-metallic full Heusler alloy Co2FeSi0.5Al0.5 with uniform thickness and B2 ordering can form structurally abrupt interface with Ge(111). Atomic resolution energy dispersive X-ray spectroscopy reveals that there is a small outdiffusion of Ge into specific atomic planes of the Co2FeSi0.5Al0.5 film, limited to a very narrow 1 nm interface region. First-principles calculations show that this selective outdiffusion along the Fe-Si/Al atomic planes does not change the magnetic moment of the film up to the very interface. Polarized neutron reflectivity, x-ray reflectivity and aberration-corrected electron microscopy confirm that this interface is both magnetically and structurally abrupt. Finally, using first-principles calculations we show that this experimentally realised interface structure, terminated by Co-Ge bonds, preserves the high spin polarization at the Co2FeSi0.5Al0.5/Ge interface, hence can be used as a model to study spin injection from half-metals into semiconductors.
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35
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Craven AJ, Bobynko J, Sala B, MacLaren I. Accurate measurement of absolute experimental inelastic mean free paths and EELS differential cross-sections. Ultramicroscopy 2016; 170:113-127. [DOI: 10.1016/j.ultramic.2016.08.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 08/12/2016] [Accepted: 08/18/2016] [Indexed: 11/15/2022]
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36
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AlAfeef A, Bobynko J, Cockshott WP, Craven AJ, Zuazo I, Barges P, MacLaren I. Linear chemically sensitive electron tomography using DualEELS and dictionary-based compressed sensing. Ultramicroscopy 2016; 170:96-106. [PMID: 27566049 DOI: 10.1016/j.ultramic.2016.08.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/26/2016] [Accepted: 08/05/2016] [Indexed: 11/29/2022]
Abstract
We have investigated the use of DualEELS in elementally sensitive tilt series tomography in the scanning transmission electron microscope. A procedure is implemented using deconvolution to remove the effects of multiple scattering, followed by normalisation by the zero loss peak intensity. This is performed to produce a signal that is linearly dependent on the projected density of the element in each pixel. This method is compared with one that does not include deconvolution (although normalisation by the zero loss peak intensity is still performed). Additionally, we compare the 3D reconstruction using a new compressed sensing algorithm, DLET, with the well-established SIRT algorithm. VC precipitates, which are extracted from a steel on a carbon replica, are used in this study. It is found that the use of this linear signal results in a very even density throughout the precipitates. However, when deconvolution is omitted, a slight density reduction is observed in the cores of the precipitates (a so-called cupping artefact). Additionally, it is clearly demonstrated that the 3D morphology is much better reproduced using the DLET algorithm, with very little elongation in the missing wedge direction. It is therefore concluded that reliable elementally sensitive tilt tomography using EELS requires the appropriate use of DualEELS together with a suitable reconstruction algorithm, such as the compressed sensing based reconstruction algorithm used here, to make the best use of the limited data volume and signal to noise inherent in core-loss EELS.
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Affiliation(s)
- Ala AlAfeef
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK; School of Computing Science, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Joanna Bobynko
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - W Paul Cockshott
- School of Computing Science, University of Glasgow, Glasgow G12 8QQ, UK
| | - Alan J Craven
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ian Zuazo
- ArcelorMittal Maizières Research, Maizières-lès-Metz 57283, France
| | - Patrick Barges
- ArcelorMittal Maizières Research, Maizières-lès-Metz 57283, France
| | - Ian MacLaren
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK.
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37
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Yankovich AB, Zhang C, Oh A, Slater TJA, Azough F, Freer R, Haigh SJ, Willett R, Voyles PM. Non-rigid registration and non-local principle component analysis to improve electron microscopy spectrum images. NANOTECHNOLOGY 2016; 27:364001. [PMID: 27479946 DOI: 10.1088/0957-4484/27/36/364001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Image registration and non-local Poisson principal component analysis (PCA) denoising improve the quality of characteristic x-ray (EDS) spectrum imaging of Ca-stabilized Nd2/3TiO3 acquired at atomic resolution in a scanning transmission electron microscope. Image registration based on the simultaneously acquired high angle annular dark field image significantly outperforms acquisition with a long pixel dwell time or drift correction using a reference image. Non-local Poisson PCA denoising reduces noise more strongly than conventional weighted PCA while preserving atomic structure more faithfully. The reliability of and optimal internal parameters for non-local Poisson PCA denoising of EDS spectrum images is assessed using tests on phantom data.
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Affiliation(s)
- Andrew B Yankovich
- Department of Materials Science and Engineering, The University of Wisconsin-Madison, 1509 University Avenue, Madison, WI 53706, USA
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38
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Atomic-level structural and chemical analysis of Cr-doped Bi2Se3 thin films. Sci Rep 2016; 6:26549. [PMID: 27221782 PMCID: PMC4879552 DOI: 10.1038/srep26549] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 05/04/2016] [Indexed: 11/18/2022] Open
Abstract
We present a study of the structure and chemical composition of the Cr-doped 3D topological insulator Bi2Se3. Single-crystalline thin films were grown by molecular beam epitaxy on Al2O3 (0001), and their structural and chemical properties determined on an atomic level by aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy. A regular quintuple layer stacking of the Bi2Se3 film is found, with the exception of the first several atomic layers in the initial growth. The spectroscopy data gives direct evidence that Cr is preferentially substituting for Bi in the Bi2Se3 host. We also show that Cr has a tendency to segregate at internal grain boundaries of the Bi2Se3 film.
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39
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Dupré N, Moreau P, De Vito E, Quazuguel L, Boniface M, Bordes A, Rudisch C, Bayle-Guillemaud P, Guyomard D. Multiprobe Study of the Solid Electrolyte Interphase on Silicon-Based Electrodes in Full-Cell Configuration. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2016; 28:2557-2572. [PMID: 27212791 PMCID: PMC4869615 DOI: 10.1021/acs.chemmater.5b04461] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 03/17/2016] [Indexed: 05/06/2023]
Abstract
The failure mechanism of silicon-based electrodes has been studied only in a half-cell configuration so far. Here, a combination of 7Li, 19F MAS NMR, XPS, TOF-SIMS, and STEM-EELS, provides an in-depth characterization of the solid electrolyte interphase (SEI) formation on the surface of silicon and its evolution upon aging and cycling with LiNi1/3Mn1/3Co1/3O2 as the positive electrode in a full Li-ion cell configuration. This multiprobe approach indicates that the electrolyte degradation process observed in the case of full Li-ion cells exhibits many similarities to what has been observed in the case of half-cells in previous works, in particular during the early stages of the cycling. Like in the case of Si/Li half-cells, the development of the inorganic part of the SEI mostly occurs during the early stage of cycling while an incessant degradation of the organic solvents of the electrolyte occurs upon cycling. However, for extended cycling, all the lithium available for cycling is consumed because of parasitic reactions and is either trapped in an intermediate part of the SEI or in the electrolyte. This nevertheless does not prevent the further degradation of the organic electrolyte solvents, leading to the formation of lithium-free organic degradation products at the extreme surface of the SEI. At this point, without any available lithium left, the cell cannot function properly anymore. Cycled positive and negative electrodes do not show any sign of particles disconnection or clogging of their porosity by electrolyte degradation products and can still function in half-cell configuration. The failure mechanism for full Li-ion cells appears then very different from that known for half-cells and is clearly due to a lack of cyclable lithium because of parasitic reactions occurring before the accumulation of electrolyte degradation products clogs the porosity of the composite electrode or disconnects the active material particles.
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Affiliation(s)
- N. Dupré
- Institut
des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
- E-mail:
| | - P. Moreau
- Institut
des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
| | - E. De Vito
- LITEN, CEA, Minatec Campus, 17 rue des Martyrs, F-38054 Grenoble, France
- Université
Grenoble Alpes, F-38000 Grenoble, France
| | - L. Quazuguel
- Institut
des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
| | - M. Boniface
- INAC-SP2M, Université Grenoble Alpes, F-38000 Grenoble, France
- INAC-SP2M, CEA, F-38054 Grenoble, France
| | - A. Bordes
- LITEN, CEA, Minatec Campus, 17 rue des Martyrs, F-38054 Grenoble, France
- Université
Grenoble Alpes, F-38000 Grenoble, France
- Groupe
de Physico-Chimie des Surfaces, Institut de Recherche de Chimie Paris, CNRS-Chimie ParisTech, 75005 Paris, France
| | - C. Rudisch
- Institut
des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
| | - P. Bayle-Guillemaud
- INAC-SP2M, Université Grenoble Alpes, F-38000 Grenoble, France
- INAC-SP2M, CEA, F-38054 Grenoble, France
| | - D. Guyomard
- Institut
des Matériaux Jean Rouxel (IMN), Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3, France
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40
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A novel 3D absorption correction method for quantitative EDX-STEM tomography. Ultramicroscopy 2016; 160:118-129. [DOI: 10.1016/j.ultramic.2015.09.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 09/18/2015] [Accepted: 09/26/2015] [Indexed: 11/24/2022]
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41
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Potapov P. Why Principal Component Analysis of STEM spectrum-images results in “abstract”, uninterpretable loadings? Ultramicroscopy 2016; 160:197-212. [DOI: 10.1016/j.ultramic.2015.10.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/19/2015] [Accepted: 10/21/2015] [Indexed: 10/22/2022]
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42
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Srivastava D, Norman C, Azough F, Schäfer MC, Guilmeau E, Kepaptsoglou D, Ramasse QM, Nicotra G, Freer R. Tuning the thermoelectric properties of A-site deficient SrTiO3 ceramics by vacancies and carrier concentration. Phys Chem Chem Phys 2016; 18:26475-26486. [PMID: 27711621 DOI: 10.1039/c6cp05523k] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The work demonstrates the relative contributions to enhanced thermoelectric performance in perovskites from (i) vacancies and (ii) charge carriers.
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Affiliation(s)
| | - Colin Norman
- School of Materials
- University of Manchester
- Manchester M13 9PL
- UK
| | - Feridoon Azough
- School of Materials
- University of Manchester
- Manchester M13 9PL
- UK
| | | | | | | | | | | | - Robert Freer
- School of Materials
- University of Manchester
- Manchester M13 9PL
- UK
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43
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MacLaren I, Sala B, Andersson SML, Pennycook TJ, Xiong J, Jia QX, Choi EM, MacManus-Driscoll JL. Strain Localization in Thin Films of Bi(Fe,Mn)O3 Due to the Formation of Stepped Mn(4+)-Rich Antiphase Boundaries. NANOSCALE RESEARCH LETTERS 2015; 10:407. [PMID: 26474888 PMCID: PMC4608946 DOI: 10.1186/s11671-015-1116-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
The atomic structure and chemistry of thin films of Bi(Fe,Mn)O3 (BFMO) films with a target composition of Bi2FeMnO6 on SrTiO3 are studied using scanning transmission electron microscopy imaging and electron energy loss spectroscopy. It is shown that Mn(4+)-rich antiphase boundaries are locally nucleated right at the film substrate and then form stepped structures that are approximately pyramidal in three dimensions. These have the effect of confining the material below the pyramids in a highly strained state with an out-of-plane lattice parameter close to 4.1 Å. Outside the area enclosed by the antiphase boundaries, the out-of-plane lattice parameter is much closer to bulk values for BFMO. This suggests that to improve the crystallographic perfection of the films whilst retaining the strain state through as much of the film as possible, ways need to be found to prevent nucleation of the antiphase boundaries. Since the antiphase boundaries seem to form from the interaction of Mn with the Ti in the substrate, one route to perform this would be to grow a thin buffer layer of pure BiFeO3 on the SrTiO3 substrate to minimise any Mn-Ti interactions.
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Affiliation(s)
- I MacLaren
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - B Sala
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - S M L Andersson
- SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
| | - T J Pennycook
- SuperSTEM Laboratory, STFC Daresbury Laboratories, Keckwick Lane, Warrington, WA4 4AD, UK
- Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH, UK
- Present Address: Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090, Vienna, Austria
| | - J Xiong
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
- State Key Lab of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, NO.4, Section 2, North Jianshe Road, Chengdu, 610054, China
| | - Q X Jia
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - E-M Choi
- Department of Materials Science, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
| | - J L MacManus-Driscoll
- Department of Materials Science, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB3 0FS, UK
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44
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Liebske C. iSpectra: An Open Source Toolbox For The Analysis of Spectral Images Recorded on Scanning Electron Microscopes. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:1006-1016. [PMID: 26165853 DOI: 10.1017/s1431927615014336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
iSpectra is an open source and system-independent toolbox for the analysis of spectral images (SIs) recorded on energy-dispersive spectroscopy (EDS) systems attached to scanning electron microscopes (SEMs). The aim of iSpectra is to assign pixels with similar spectral content to phases, accompanied by cumulative phase spectra with superior counting statistics for quantification. Pixel-to-phase assignment starts with a threshold-based pre-sorting of spectra to create groups of pixels with identical elemental budgets, similar to a method described by van Hoek (2014). Subsequent merging of groups and re-assignments of pixels using elemental or principle component histogram plots enables the user to generate chemically and texturally plausible phase maps. A variety of standard image processing algorithms can be applied to groups of pixels to optimize pixel-to-phase assignments, such as morphology operations to account for overlapping excitation volumes over pixels located at phase boundaries. iSpectra supports batch processing and allows pixel-to-phase assignments to be applied to an unlimited amount of SIs, thus enabling phase mapping of large area samples like petrographic thin sections.
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Affiliation(s)
- Christian Liebske
- Department of Earth Sciences,Institute of Geochemistry and Petrology,ETH Zürich,Sonneggstrasse 5,8092 Zürich,Switzerland
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45
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Alix K, David ML, Lucas G, Alexander DTL, Pailloux F, Hébert C, Pizzagalli L. Gentle quantitative measurement of helium density in nanobubbles in silicon by spectrum imaging. Micron 2015; 77:57-65. [PMID: 26093479 DOI: 10.1016/j.micron.2015.05.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/19/2015] [Accepted: 05/19/2015] [Indexed: 11/19/2022]
Abstract
We propose an original method for the determination of the physical properties of nanometer sized helium bubbles using spectrum imaging in an energy-filtered transmission electron microscope. Helium bubbles synthesized by high fluence implantation and thermal annealing in silicon are investigated. The acquisition parameters are determined to optimize both signal/noise ratio and time. The limitations to the extent of observable areas on a typical sample are explained. The necessary data correction and helium K-edge position measurement procedures are detailed and the accuracy of the method is discussed. Finally helium density maps are obtained and discussed.
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Affiliation(s)
- Kévin Alix
- Institut Pprime, UPR3346 CNRS-Université de Poitiers, 86962 Futuroscope-Chasseneuil, France
| | - Marie-Laure David
- Institut Pprime, UPR3346 CNRS-Université de Poitiers, 86962 Futuroscope-Chasseneuil, France.
| | | | | | - Frédéric Pailloux
- Institut Pprime, UPR3346 CNRS-Université de Poitiers, 86962 Futuroscope-Chasseneuil, France
| | - Cécile Hébert
- CIME, EPFL-SB-CIME-GE, CH-1015 Lausanne, Switzerland
| | - Laurent Pizzagalli
- Institut Pprime, UPR3346 CNRS-Université de Poitiers, 86962 Futuroscope-Chasseneuil, France
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46
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Rossouw D, Burdet P, de la
Peña F, Ducati C, Knappett B, Wheatley AEH, Midgley PA. Multicomponent signal unmixing from nanoheterostructures: overcoming the traditional challenges of nanoscale X-ray analysis via machine learning. NANO LETTERS 2015; 15:2716-20. [PMID: 25760234 PMCID: PMC4440406 DOI: 10.1021/acs.nanolett.5b00449] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/06/2015] [Indexed: 05/25/2023]
Abstract
The chemical composition of core-shell nanoparticle clusters have been determined through principal component analysis (PCA) and independent component analysis (ICA) of an energy-dispersive X-ray (EDX) spectrum image (SI) acquired in a scanning transmission electron microscope (STEM). The method blindly decomposes the SI into three components, which are found to accurately represent the isolated and unmixed X-ray signals originating from the supporting carbon film, the shell, and the bimetallic core. The composition of the latter is verified by and is in excellent agreement with the separate quantification of bare bimetallic seed nanoparticles.
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Affiliation(s)
- David Rossouw
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Pierre Burdet
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Francisco de la
Peña
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Caterina Ducati
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
| | - Benjamin
R. Knappett
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Andrew E. H. Wheatley
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Paul A. Midgley
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles
Babbage Road, Cambridge CB3 0FS, United Kingdom
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47
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Spectrum imaging of complex nanostructures using DualEELS: I. digital extraction replicas. Ultramicroscopy 2015; 149:9-20. [DOI: 10.1016/j.ultramic.2014.10.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/16/2014] [Accepted: 10/26/2014] [Indexed: 11/19/2022]
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48
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Burdet P, Croxall SA, Midgley PA. Enhanced quantification for 3D SEM-EDS: using the full set of available X-ray lines. Ultramicroscopy 2014; 148:158-167. [PMID: 25461593 PMCID: PMC4266451 DOI: 10.1016/j.ultramic.2014.10.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/01/2014] [Accepted: 10/05/2014] [Indexed: 11/25/2022]
Abstract
An enhanced method to quantify energy dispersive spectra recorded in 3D with a scanning electron microscope (3D SEM–EDS) has been previously demonstrated. This paper presents an extension of this method using all the available X-ray lines generated by the beam. The extended method benefits from using high energy lines, that are more accurately quantified, and from using soft X-rays that are highly absorbed and thus more surface sensitive. The data used to assess the method are acquired with a dual beam FIB/SEM investigating a multi-element Ni-based superalloy. A high accelerating voltage, needed to excite the highest energy X-ray line, results in two available X-ray lines for several elements. The method shows an improved compositional quantification as well as an improved spatial resolution. 3D SEM–EDS mapping of structures smaller than the X-ray generation volume is considered. The influence of neighbouring voxels is corrected by a recursive quantification method. The method is improved using all available X-ray lines. The method is applied to simulated spectra and experimental dual beam FIB/SEM data. The method is shown to improve both compositional accuracy and spatial resolution.
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Affiliation(s)
- Pierre Burdet
- Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge, CB3 0FS Cambridgeshire, UK.
| | - S A Croxall
- Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge, CB3 0FS Cambridgeshire, UK
| | - P A Midgley
- Department of Materials Science and Metallurgy, University of Cambridge, Charles Babbage Road 27, Cambridge, CB3 0FS Cambridgeshire, UK
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49
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Burdet P, Hébert C, Cantoni M. Enhanced quantification for 3D energy dispersive spectrometry: going beyond the limitation of large volume of X-ray emission. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:1544-1555. [PMID: 24960631 DOI: 10.1017/s1431927614001688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This paper presents a method developed to quantify three-dimensional energy dispersive spectrometry (3D EDS) data with voxel size smaller than the volume from which X-rays are emitted. The influence of the neighboring voxels is corrected by applying recursively a complex quantification, improving thereby the accuracy of the quantification of critically small features. The enhanced quantification method is applied to simulated and measured data. A systematic improvement is obtained compared with classical quantification, proving the concept and the prospect of this method.
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Affiliation(s)
- Pierre Burdet
- 1Department of Materials Science and Metallurgy,University of Cambridge,Charles Babbage Road 27,Cambridge CB3 0FS,Cambridgeshire,UK
| | - Cécile Hébert
- 2Centre Interdisciplinaire de Microscopie Electronique,Ecole Polytechnique Fédérale de Lausanne (EPFL),Station 12,Lausanne 1015,Switzerland
| | - Marco Cantoni
- 2Centre Interdisciplinaire de Microscopie Electronique,Ecole Polytechnique Fédérale de Lausanne (EPFL),Station 12,Lausanne 1015,Switzerland
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