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Hage FS, Radtke G, Kepaptsoglou DM, Lazzeri M, Ramasse QM. Single-atom vibrational spectroscopy in the scanning transmission electron microscope. Science 2020; 367:1124-1127. [PMID: 32139541 DOI: 10.1126/science.aba1136] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/03/2020] [Indexed: 11/02/2022]
Abstract
Single-atom impurities and other atomic-scale defects can notably alter the local vibrational responses of solids and, ultimately, their macroscopic properties. Using high-resolution electron energy-loss spectroscopy in the electron microscope, we show that a single substitutional silicon impurity in graphene induces a characteristic, localized modification of the vibrational response. Extensive ab initio calculations reveal that the measured spectroscopic signature arises from defect-induced pseudo-localized phonon modes-that is, resonant states resulting from the hybridization of the defect modes and the bulk continuum-with energies that can be directly matched to the experiments. This finding realizes the promise of vibrational spectroscopy in the electron microscope with single-atom sensitivity and has broad implications across the fields of physics, chemistry, and materials science.
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Affiliation(s)
- F S Hage
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, UK
| | - G Radtke
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, 75005 Paris, France.
| | - D M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, UK.,York Nanocentre and Department of Physics, University of York, Heslington, York YO10 5DD, UK
| | - M Lazzeri
- Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, 75005 Paris, France
| | - Q M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, UK. .,School of Chemical and Process Engineering and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK
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Kim E, Agarwal S, Kim N, Hage FS, Leonardo V, Gelmi A, Stevens MM. Bioinspired Fabrication of DNA-Inorganic Hybrid Composites Using Synthetic DNA. ACS Nano 2019; 13:2888-2900. [PMID: 30741535 PMCID: PMC6439439 DOI: 10.1021/acsnano.8b06492] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 02/06/2019] [Indexed: 05/19/2023]
Abstract
Nucleic acid nanostructures have attracted significant interest as potential therapeutic and diagnostic platforms due to their intrinsic biocompatibility and biodegradability, structural and functional diversity, and compatibility with various chemistries for modification and stabilization. Among the fabrication approaches for such structures, the rolling circle techniques have emerged as particularly promising, producing morphologically round, flower-shaped nucleic acid particles: typically hybrid composites of long nucleic acid strands and inorganic magnesium pyrophosphate (Mg2PPi). These constructs are known to form via anisotropic nucleic acid-driven crystallization in a sequence-independent manner, rendering monodisperse and densely packed RNA or DNA-inorganic composites. However, it still remains to fully explore how flexible polymer-like RNA or DNA strands (acting as biomolecular additives) mediate the crystallization process of Mg2PPi and affect the structure and properties of the product crystals. To address this, we closely examined nanoscale details to mesoscopic features of Mg2PPi/DNA hybrid composites fabricated by two approaches, namely rolling circle amplification (RCA)-based in situ synthesis and long synthetic DNA-mediated crystallization. Similar to the DNA constructs fabricated by RCA, the rapid crystallization of Mg2PPi was retarded on a short-range order when we precipitated the crystals in the presence of presynthesized long DNA, which resulted in effective incorporation of biomolecular additives such as DNA and enzymes. These findings further provide a more feasible way to encapsulate bioactive enzymes within DNA constructs compared to in situ RCA-mediated synthesis, i.e., by not only protecting them from possible denaturation under the reaction conditions but also preventing nonselective association of proteins arising from the RCA reaction mixtures.
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Affiliation(s)
- Eunjung Kim
- Department
of Materials, Department of Bioengineering and Institute for Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Shweta Agarwal
- Department
of Materials, Department of Bioengineering and Institute for Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Nayoung Kim
- Department
of Materials, Department of Bioengineering and Institute for Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Fredrik Sydow Hage
- SuperSTEM
Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
| | - Vincent Leonardo
- Department
of Materials, Department of Bioengineering and Institute for Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Amy Gelmi
- Department
of Materials, Department of Bioengineering and Institute for Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - Molly M. Stevens
- Department
of Materials, Department of Bioengineering and Institute for Biomedical
Engineering, Imperial College London, London SW7 2AZ, United Kingdom
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Abstract
Advances in source monochromation in transmission electron microscopy have opened up new possibilities for investigations of condensed matter using the phonon-loss sector of the energy-loss spectrum. Here, we explore the spatial variations of the spectrum as an atomic-sized probe is scanned across a thin flake of hexagonal boron nitride. We demonstrate that phonon spectral mapping of atomic structure is possible. These results are consistent with a model for the quantum excitation of phonons and confirm that Z-contrast imaging is based on inelastic scattering associated with phonon excitation.
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Affiliation(s)
- F S Hage
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
| | - D M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
- York JEOL Nanocentre and Department of Physics, University of York, Heslington, York YO10 5BR, United Kingdom
| | - Q M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
- School of Physics and School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - L J Allen
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich, 52425 Jülich, Germany
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Hage FS, Hardcastle TP, Gjerding MN, Kepaptsoglou DM, Seabourne CR, Winther KT, Zan R, Amani JA, Hofsaess HC, Bangert U, Thygesen KS, Ramasse QM. Local Plasmon Engineering in Doped Graphene. ACS Nano 2018; 12:1837-1848. [PMID: 29369611 DOI: 10.1021/acsnano.7b08650] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Single-atom B or N substitutional doping in single-layer suspended graphene, realized by low-energy ion implantation, is shown to induce a dampening or enhancement of the characteristic interband π plasmon of graphene through a high-resolution electron energy loss spectroscopy study using scanning transmission electron microscopy. A relative 16% decrease or 20% increase in the π plasmon quality factor is attributed to the presence of a single substitutional B or N atom dopant, respectively. This modification is in both cases shown to be relatively localized, with data suggesting the plasmonic response tailoring can no longer be detected within experimental uncertainties beyond a distance of approximately 1 nm from the dopant. Ab initio calculations confirm the trends observed experimentally. Our results directly confirm the possibility of tailoring the plasmonic properties of graphene in the ultraviolet waveband at the atomic scale, a crucial step in the quest for utilizing graphene's properties toward the development of plasmonic and optoelectronic devices operating at ultraviolet frequencies.
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Affiliation(s)
| | - Trevor P Hardcastle
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Morten N Gjerding
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Demie M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- York NanoCentre, University of York , Heslington, York YO10 5BR, U.K
| | - Che R Seabourne
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
| | - Kirsten T Winther
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Recep Zan
- Nanotechnology Application and Research Center, Niğde Omer Halisdemir University , Niğde 51000, Turkey
| | - Julian Alexander Amani
- II Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Hans C Hofsaess
- II Physikalisches Institut, Georg-August-Universität Göttingen , Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
| | - Ursel Bangert
- Bernal Institute and Department of Physics, University of Limerick , Limerick, Ireland
| | - Kristian S Thygesen
- CAMD and Center for Nanostructured Graphene (CNG), Technical University of Denmark , Fysikvej 1, Building 307, 2800 Kgs. Lyngby, Denmark
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, U.K
- School of Chemical and Process Engineering, University of Leeds , Leeds LS2 9JT, U.K
- School of Physics, University of Leeds , Leeds LS2 9JT, U.K
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Hage FS, Kepaptsoglou DM, Seabourne CR, Ramasse QM, Scott AJ, Prytz Ø, Gunnæs AE, Helgesen G. Dielectric response of pentagonal defects in multilayer graphene nano-cones. Nanoscale 2014; 6:1833-1839. [PMID: 24356681 DOI: 10.1039/c3nr05419e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The dielectric response of pentagonal defects in multilayer graphene nano-cones has been studied by electron energy loss spectroscopy and ab initio simulations. At the cone apex, a strong modification of the dielectric response is observed below the energy of the π plasmon resonance. This is attributed to π → π* interband transitions induced by topology-specific resonant π bonding states as well as π*-σ* hybridization. It is concluded that pentagonal defects strongly affect the local electronic structure in such a way that multi-walled graphene nano-cones should show great promise as field emitters.
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Affiliation(s)
- F S Hage
- SuperSTEM Laboratory, SciTech Daresbury, Keckwick Lane, Daresbury, WA4 4AD, UK.
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Sartori S, Knudsen KD, Hage FS, Heyn RH, Bardaji EG, Zhao-Karger Z, Fichtner M, Hauback BC. Influence of nanoconfinement on morphology and dehydrogenation of the Li11BD4-Mg(11BD4)2 system. Nanotechnology 2012; 23:255704. [PMID: 22652690 DOI: 10.1088/0957-4484/23/25/255704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The decomposition of a nanoconfined mixture of lithium-magnesium borohydride, Li(11)BD(4)-Mg((11)BD(4))(2), has been investigated and compared to the corresponding mixture in the bulk form. The systems were investigated by thermal analysis, small-angle neutron scattering, (11)B nuclear magnetic resonance and transmission electron microscopy. The dehydrogenation temperatures decreased by up to 60 °C in the nanoconfined system, with gas evolution following different steps, compared to the behaviour of the bulk material under the same conditions. Most importantly, desorption from the nanoconfined hydride proceeds without formation of diborane, B(2)D(6), which evolves from the bulk mixture. From small-angle neutron scattering, differences in morphology between the bulk and the nanoconfined systems are also demonstrated. Evidence of a complete decomposition has been found in the nanoconfined system, after heating up to 460 °C. Furthermore, (11)B NMR data show that nanoconfinement inhibits the formation of dodecaborane, [B(12)D(12)](2-), during decomposition, a result which is important for practical applications of borohydrides.
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