1
|
Willhammar T, Sentosun K, Mourdikoudis S, Goris B, Bercx M, Lamoen D, Partoens B, Liz-Marzan LM, Bals S, van Tendeloo G. Real and reciprocal space electron tomography reveals structure and vacancies. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s205327331709218x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
2
|
De Backer A, Jones L, Lobato I, Altantzis T, Goris B, Nellist PD, Bals S, Van Aert S. Three-dimensional atomic models from a single projection using Z-contrast imaging: verification by electron tomography and opportunities. Nanoscale 2017; 9:8791-8798. [PMID: 28621785 DOI: 10.1039/c7nr02656k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In order to fully exploit structure-property relations of nanomaterials, three-dimensional (3D) characterization at the atomic scale is often required. In recent years, the resolution of electron tomography has reached the atomic scale. However, such tomography typically requires several projection images demanding substantial electron dose. A newly developed alternative circumvents this by counting the number of atoms across a single projection. These atom counts can be used to create an initial atomic model with which an energy minimization can be applied to obtain a relaxed 3D reconstruction of the nanoparticle. Here, we compare, at the atomic scale, this single projection reconstruction approach with tomography and find an excellent agreement. This new approach allows for the characterization of beam-sensitive materials or where the acquisition of a tilt series is impossible. As an example, the utility is illustrated by the 3D atomic scale characterization of a nanodumbbell on an in situ heating holder of limited tilt range.
Collapse
Affiliation(s)
- A De Backer
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Peters JL, van den Bos KHW, Van Aert S, Goris B, Bals S, Vanmaekelbergh D. Ligand-Induced Shape Transformation of PbSe Nanocrystals. Chem Mater 2017; 29:4122-4128. [PMID: 28503030 PMCID: PMC5425942 DOI: 10.1021/acs.chemmater.7b01103] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/06/2017] [Indexed: 05/22/2023]
Abstract
We present a study of the relation between the surface chemistry and nanocrystal shape of PbSe nanocrystals with a variable Pb-to-Se stoichiometry and density of oleate ligands. The oleate ligand density and binding configuration are monitored by nuclear magnetic resonance and Fourier transform infrared absorbance spectroscopy, allowing us to quantify the number of surface-attached ligands per NC and the nature of the surface-Pb-oleate configuration. The three-dimensional shape of the PbSe nanocrystals is obtained from high-angle annular dark field scanning transmission electron microscopy combined with an atom counting method. We show that the enhanced oleate capping results in a stabilization and extension of the {111} facets, and a crystal shape transformation from a truncated nanocube to a truncated octahedron.
Collapse
Affiliation(s)
- Joep L. Peters
- Debye
Institute for Nanomaterials Science, University
of Utrecht, Utrecht, The Netherlands
| | | | | | - Bart Goris
- EMAT, University
of Antwerp, Antwerpen, Belgium
| | - Sara Bals
- EMAT, University
of Antwerp, Antwerpen, Belgium
| | - Daniël Vanmaekelbergh
- Debye
Institute for Nanomaterials Science, University
of Utrecht, Utrecht, The Netherlands
- E-mail:
| |
Collapse
|
4
|
Albrecht W, Goris B, Bals S, Hutter EM, Vanmaekelbergh D, van Huis MA, van Blaaderen A. Morphological and chemical transformations of single silica-coated CdSe/CdS nanorods upon fs-laser excitation. Nanoscale 2017; 9:4810-4818. [PMID: 28352861 DOI: 10.1039/c6nr09879g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Radiation-induced modifications of nanostructures are of fundamental interest and constitute a viable out-of-equilibrium approach to the development of novel nanomaterials. Herein, we investigated the structural transformation of silica-coated CdSe/CdS nanorods (NRs) under femtosecond (fs) illumination. By comparing the same nanorods before and after illumination with different fluences we found that the silica-shell did not only enhance the stability of the NRs but that the confinement of the NRs also led to novel morphological and chemical transformations. Whereas uncoated CdSe/CdS nanorods were found to sublimate under such excitations the silica-coated nanorods broke into fragments which deformed towards a more spherical shape. Furthermore, CdS decomposed which led to the formation of metallic Cd, confirmed by high-resolution electron microscopy and energy dispersive X-ray spectrometry (EDX), whereby an epitaxial interface with the remaining CdS lattice was formed. Under electron beam exposure similar transformations were found to take place which we followed in situ.
Collapse
Affiliation(s)
- Wiebke Albrecht
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
| | - Bart Goris
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sara Bals
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Eline M Hutter
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
| | - Daniel Vanmaekelbergh
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
| | - Marijn A van Huis
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
| | - Alfons van Blaaderen
- Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
| |
Collapse
|
5
|
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] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 10/11/2016] [Accepted: 12/08/2016] [Indexed: 11/17/2022]
|
6
|
Geuchies JJ, van Overbeek C, Evers WH, Goris B, de Backer A, Gantapara AP, Rabouw FT, Hilhorst J, Peters JL, Konovalov O, Petukhov AV, Dijkstra M, Siebbeles LDA, van Aert S, Bals S, Vanmaekelbergh D. In situ study of the formation mechanism of two-dimensional superlattices from PbSe nanocrystals. Nat Mater 2016; 15:1248-1254. [PMID: 27595349 DOI: 10.1038/nmat4746] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 07/27/2016] [Indexed: 05/20/2023]
Abstract
Oriented attachment of PbSe nanocubes can result in the formation of two-dimensional (2D) superstructures with long-range nanoscale and atomic order. This questions the applicability of classic models in which the superlattice grows by first forming a nucleus, followed by sequential irreversible attachment of nanocrystals, as one misaligned attachment would disrupt the 2D order beyond repair. Here, we demonstrate the formation mechanism of 2D PbSe superstructures with square geometry by using in situ grazing-incidence X-ray scattering (small angle and wide angle), ex situ electron microscopy, and Monte Carlo simulations. We observed nanocrystal adsorption at the liquid/gas interface, followed by the formation of a hexagonal nanocrystal monolayer. The hexagonal geometry transforms gradually through a pseudo-hexagonal phase into a phase with square order, driven by attractive interactions between the {100} planes perpendicular to the liquid substrate, which maximize facet-to-facet overlap. The nanocrystals then attach atomically via a necking process, resulting in 2D square superlattices.
Collapse
Affiliation(s)
- Jaco J Geuchies
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
- ID10, European Synchrotron Radiation Facility (ESRF), 38000 Grenoble, France
| | - Carlo van Overbeek
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Wiel H Evers
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands
- Kavli Institute of Nanoscience, Delft University of Technology, 2628 CJ Delft, The Netherlands
| | - Bart Goris
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium
| | - Annick de Backer
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium
| | - Anjan P Gantapara
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Freddy T Rabouw
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Jan Hilhorst
- ID01, European Synchrotron Radiation Facility (ESRF), 38000 Grenoble, France
| | - Joep L Peters
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Oleg Konovalov
- ID10, European Synchrotron Radiation Facility (ESRF), 38000 Grenoble, France
| | - Andrei V Petukhov
- Physical and Colloidal Chemistry, Debye Institute for Nanomaterials Science, Utrecht University, 3508 TB Utrecht, The Netherlands
- Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Marjolein Dijkstra
- Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| | - Laurens D A Siebbeles
- Optoelectronic Materials Section, Department of Chemical Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Sandra van Aert
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium
| | - Sara Bals
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, 2020 Antwerp, Belgium
| | - Daniel Vanmaekelbergh
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, 3584 CC Utrecht, The Netherlands
| |
Collapse
|
7
|
Goris B, Meledina M, Turner S, Zhong Z, Batenburg KJ, Bals S. Three dimensional mapping of Fe dopants in ceria nanocrystals using direct spectroscopic electron tomography. Ultramicroscopy 2016; 171:55-62. [DOI: 10.1016/j.ultramic.2016.08.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/22/2016] [Accepted: 08/29/2016] [Indexed: 11/26/2022]
|
8
|
Kinnear C, Rodriguez-Lorenzo L, Clift MJD, Goris B, Bals S, Rothen-Rutishauser B, Petri-Fink A. Decoupling the shape parameter to assess gold nanorod uptake by mammalian cells. Nanoscale 2016; 8:16416-16426. [PMID: 27714053 DOI: 10.1039/c6nr03543d] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The impact of nanoparticles (NPs) upon biological systems can be fundamentally associated with their physicochemical parameters. A further often-stated tenet is the importance of NP shape on rates of endocytosis. However, given the convoluted parameters concerning the NP-cell interaction, it is experimentally challenging to attribute any findings to shape alone. Herein we demonstrate that shape, below a certain limit, which is specific to nanomedicine, is not important for the endocytosis of spherocylinders by either epithelial or macrophage cells in vitro. Through a systematic approach, we reshaped a single batch of gold nanorods into different aspect ratios resulting in near-spheres and studied their cytotoxicity, (pro-)inflammatory status, and endocytosis/exocytosis. It was found that on a length scale of ∼10-90 nm and at aspect ratios less than 5, NP shape has little impact upon their entry into either macrophages or epithelial cells. Conversely, nanorods with an aspect ratio above 5 were preferentially endocytosed by epithelial cells, whereas there was a lack of shape dependent uptake following exposure to macrophages in vitro. These findings have implications both in the understanding of nanoparticle reshaping mechanisms, as well as in the future rational design of nanomaterials for biomedical applications.
Collapse
Affiliation(s)
- C Kinnear
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland
| | - L Rodriguez-Lorenzo
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland
| | - M J D Clift
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland
| | - B Goris
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Antwerp 2020, Belgium
| | - S Bals
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Antwerp 2020, Belgium
| | | | - A Petri-Fink
- Adolphe Merkle Institute, University of Fribourg, Fribourg 1700, Switzerland and Chemistry Department, University of Fribourg, Fribourg 1700, Switzerland.
| |
Collapse
|
9
|
Albrecht W, Deng TS, Goris B, van Huis M, Bals S, van Blaaderen A. Single Particle Deformation and Analysis of Silica-Coated Gold Nanorods before and after Femtosecond Laser Pulse Excitation. Nano Lett 2016; 16:1818-25. [PMID: 26871607 PMCID: PMC4973961 DOI: 10.1021/acs.nanolett.5b04851] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We performed single particle deformation experiments on silica-coated gold nanorods under femtosecond (fs) illumination. Changes in the particle shape were analyzed by electron microscopy and associated changes in the plasmon resonance by electron energy loss spectroscopy. Silica-coated rods were found to be more stable compared to uncoated rods but could still be deformed via an intermediate bullet-like shape for silica shell thicknesses of 14 nm. Changes in the size ratio of the rods after fs-illumination resulted in blue-shifting of the longitudinal plasmon resonances. Two-dimensional spatial mapping of the plasmon resonances revealed that the flat side of the bullet-like particles showed a less pronounced longitudinal plasmonic electric field enhancement. These findings were confirmed by finite-difference time-domain (FDTD) simulations. Furthermore, at higher laser fluences size reduction of the particles was found as well as for particles that were not completely deformed yet.
Collapse
Affiliation(s)
- Wiebke Albrecht
- Soft Condensed
Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
- E-mail:
| | - Tian-Song Deng
- Soft Condensed
Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Bart Goris
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Marijn
A. van Huis
- Soft Condensed
Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Sara Bals
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Alfons van Blaaderen
- Soft Condensed
Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
- E-mail:
| |
Collapse
|
10
|
Goris B, De Beenhouwer J, De Backer A, Zanaga D, Batenburg KJ, Sánchez-Iglesias A, Liz-Marzán LM, Van Aert S, Bals S, Sijbers J, Van Tendeloo G. Measuring Lattice Strain in Three Dimensions through Electron Microscopy. Nano Lett 2015; 15:6996-7001. [PMID: 26340328 PMCID: PMC4877113 DOI: 10.1021/acs.nanolett.5b03008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The three-dimensional (3D) atomic structure of nanomaterials, including strain, is crucial to understand their properties. Here, we investigate lattice strain in Au nanodecahedra using electron tomography. Although different electron tomography techniques enabled 3D characterizations of nanostructures at the atomic level, a reliable determination of lattice strain is not straightforward. We therefore propose a novel model-based approach from which atomic coordinates are measured. Our findings demonstrate the importance of investigating lattice strain in 3D.
Collapse
Affiliation(s)
- Bart Goris
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Jan De Beenhouwer
- iMinds-Vision
Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Annick De Backer
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Daniele Zanaga
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - K. Joost Batenburg
- Centrum Wiskunde
& Informatica, P.O. Box 94079, 1090 GB Amsterdam, The Netherlands
| | - Ana Sánchez-Iglesias
- Bionanoplasmonics
Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia - San Sebastian, Spain
| | - Luis M. Liz-Marzán
- Bionanoplasmonics
Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia - San Sebastian, Spain
- Ikerbasque, Basque
Foundation for Science, 48013 Bilbao, Spain
| | - Sandra Van Aert
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sara Bals
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- E-mail:
| | - Jan Sijbers
- iMinds-Vision
Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Gustaaf Van Tendeloo
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| |
Collapse
|
11
|
Yalcin AO, Goris B, van Dijk-Moes RJA, Fan Z, Erdamar AK, Tichelaar FD, Vlugt TJH, Van Tendeloo G, Bals S, Vanmaekelbergh D, Zandbergen HW, van Huis MA. Heat-induced transformation of CdSe-CdS-ZnS core-multishell quantum dots by Zn diffusion into inner layers. Chem Commun (Camb) 2015; 51:3320-3. [PMID: 25431813 DOI: 10.1039/c4cc08647c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work, we investigate the thermal evolution of CdSe-CdS-ZnS core-multishell quantum dots (QDs) in situ using transmission electron microscopy (TEM). Starting at a temperature of approximately 250 °C, Zn diffusion into inner layers takes place together with simultaneous evaporation of particularly Cd and S. As a result of this transformation, CdxZn1-xSe-CdyZn1-yS core-shell QDs are obtained.
Collapse
Affiliation(s)
- Anil O Yalcin
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Chen D, Goris B, Bleichrodt F, Mezerji HH, Bals S, Batenburg KJ, de With G, Friedrich H. The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections. Ultramicroscopy 2014; 147:137-48. [DOI: 10.1016/j.ultramic.2014.08.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/25/2014] [Accepted: 08/03/2014] [Indexed: 10/24/2022]
|
13
|
Hutter E, Bladt E, Goris B, Pietra F, van der Bok JC, Boneschanscher MP, de Mello
Donegá C, Bals S, Vanmaekelbergh D. Conformal and atomic characterization of ultrathin CdSe platelets with a helical shape. Nano Lett 2014; 14:6257-62. [PMID: 25347528 PMCID: PMC4425435 DOI: 10.1021/nl5025744] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 10/20/2014] [Indexed: 05/22/2023]
Abstract
Currently, ultrathin colloidal CdSe semiconductor nanoplatelets (NPLs) with a uniform thickness that is controllable up to the atomic scale can be prepared. The optical properties of these 2D semiconductor systems are the subject of extensive research. Here, we reveal their natural morphology and atomic arrangement. Using cryo-TEM (cryo-transmission electron microscopy), we show that the shape of rectangular NPLs in solution resembles a helix. Fast incorporation of these NPLs in silica preserves and immobilizes their helical shape, which allowed us to perform an in-depth study by high angle annular dark field scanning transmission electron microscopy (HAADF-STEM). Electron tomography measurements confirm and detail the helical shape of these systems. Additionally, high-resolution HAADF-STEM shows the thickness of the NPLs on the atomic scale and furthermore that these are consistently folded along a ⟨110⟩ direction. The presence of a silica shell on both the top and bottom surfaces shows that Cd atoms must be accessible for silica precursor (and ligand) molecules on both sides.
Collapse
Affiliation(s)
- Eline
M. Hutter
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Eva Bladt
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Bart Goris
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Francesca Pietra
- Opto-electronic
Materials Section, Department of Chemical Engineering, Delft University of Technology, Julianalaan 136, 2628 BL Delft, The Netherlands
| | - Johanna C. van der Bok
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Mark P. Boneschanscher
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Celso de Mello
Donegá
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
| | - Sara Bals
- Electron
Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Daniël Vanmaekelbergh
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, 3584 CC Utrecht, The Netherlands
- E-mail:
| |
Collapse
|
14
|
Abstract
Using electron tomography combined with electron energy loss spectroscopy (EELS), we are able to map the valency of the Ce ions in CeO2-x nanocrystals in three dimensions. Our results show a clear facet-dependent reduction shell at the surface of ceria nanoparticles; {111} surface facets show a low surface reduction, whereas at {001} surface facets, the cerium ions are more likely to be reduced over a larger surface shell. Our generic tomographic technique allows a full 3D data cube to be reconstructed, containing an EELS spectrum in each voxel. This possibility enables a three-dimensional investigation of a plethora of material-specific physical properties such as valency, chemical composition, oxygen coordination, or bond lengths, triggering the synthesis of nanomaterials with improved properties.
Collapse
Affiliation(s)
- Bart Goris
- EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | | | | | | |
Collapse
|
15
|
Bals S, Goris B, Liz-Marzán L, Van Tendeloo G. Dreidimensionale Charakterisierung von Edelmetall-Nanopartikeln und deren Anordnungen mithilfe von Elektronentomographie. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201401059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
16
|
Bals S, Goris B, Liz-Marzán LM, Van Tendeloo G. Three-Dimensional Characterization of Noble-Metal Nanoparticles and their Assemblies by Electron Tomography. Angew Chem Int Ed Engl 2014; 53:10600-10. [DOI: 10.1002/anie.201401059] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Indexed: 11/11/2022]
|
17
|
Goris B, Guzzinati G, Fernández-López C, Pérez-Juste J, Liz-Marzán LM, Trügler A, Hohenester U, Verbeeck J, Bals S, Van Tendeloo G. Plasmon Mapping in Au@Ag Nanocube Assemblies. J Phys Chem C Nanomater Interfaces 2014; 118:15356-15362. [PMID: 25067991 PMCID: PMC4106270 DOI: 10.1021/jp502584t] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 06/27/2014] [Indexed: 05/15/2023]
Abstract
Surface plasmon modes in metallic nanostructures largely determine their optoelectronic properties. Such plasmon modes can be manipulated by changing the morphology of the nanoparticles or by bringing plasmonic nanoparticle building blocks close to each other within organized assemblies. We report the EELS mapping of such plasmon modes in pure Ag nanocubes, Au@Ag core-shell nanocubes, and arrays of Au@Ag nanocubes. We show that these arrays enable the creation of interesting plasmonic structures starting from elementary building blocks. Special attention will be dedicated to the plasmon modes in a triangular array formed by three nanocubes. Because of hybridization, a combination of such nanotriangles is shown to provide an antenna effect, resulting in strong electrical field enhancement at the narrow gap between the nanotriangles.
Collapse
Affiliation(s)
- Bart Goris
- EMAT, University
of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Giulio Guzzinati
- EMAT, University
of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | | | - Jorge Pérez-Juste
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
| | - Luis M. Liz-Marzán
- Departamento de Química Física, Universidade de Vigo, 36310 Vigo, Spain
- BioNanoPlasmonics
Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia - San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain
| | - Andreas Trügler
- Institut
für Physik, Karl-Franzens-Universität
Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - Ulrich Hohenester
- Institut
für Physik, Karl-Franzens-Universität
Graz, Universitätsplatz
5, 8010 Graz, Austria
| | - Jo Verbeeck
- EMAT, University
of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Sara Bals
- EMAT, University
of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | | |
Collapse
|
18
|
Yalcin AO, Fan Z, Goris B, Li WF, Koster RS, Fang CM, van Blaaderen A, Casavola M, Tichelaar FD, Bals S, Van Tendeloo G, Vlugt TJH, Vanmaekelbergh D, Zandbergen H, van
Huis MA. Atomic resolution monitoring of cation exchange in CdSe-PbSe heteronanocrystals during epitaxial solid-solid-vapor growth. Nano Lett 2014; 14:3661-7. [PMID: 24844280 PMCID: PMC4055051 DOI: 10.1021/nl501441w] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 05/15/2014] [Indexed: 05/25/2023]
Abstract
Here, we show a novel solid-solid-vapor (SSV) growth mechanism whereby epitaxial growth of heterogeneous semiconductor nanowires takes place by evaporation-induced cation exchange. During heating of PbSe-CdSe nanodumbbells inside a transmission electron microscope (TEM), we observed that PbSe nanocrystals grew epitaxially at the expense of CdSe nanodomains driven by evaporation of Cd. Analysis of atomic-resolution TEM observations and detailed atomistic simulations reveals that the growth process is mediated by vacancies.
Collapse
Affiliation(s)
- Anil O. Yalcin
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
| | - Zhaochuan Fan
- Process
and Energy Laboratory, Delft University
of Technology, Leeghwaterstraat
39, 2628 CB Delft, The Netherlands
| | - Bart Goris
- Electron
Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Wun-Fan Li
- Soft
Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Rik S. Koster
- Soft
Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Chang-Ming Fang
- Soft
Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Alfons van Blaaderen
- Soft
Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Marianna Casavola
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Frans D. Tichelaar
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
| | - Sara Bals
- Electron
Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Gustaaf Van Tendeloo
- Electron
Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Thijs J. H. Vlugt
- Process
and Energy Laboratory, Delft University
of Technology, Leeghwaterstraat
39, 2628 CB Delft, The Netherlands
| | - Daniël Vanmaekelbergh
- Condensed
Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| | - Henny
W. Zandbergen
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
| | - Marijn A. van
Huis
- Kavli
Institute of Nanoscience, Delft University
of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
- Soft
Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands
| |
Collapse
|
19
|
Goris B, Polavarapu L, Bals S, Van Tendeloo G, Liz-Marzán LM. Monitoring galvanic replacement through three-dimensional morphological and chemical mapping. Nano Lett 2014; 14:3220-6. [PMID: 24798989 DOI: 10.1021/nl500593j] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Galvanic replacement reactions on metal nanoparticles are often used for the preparation of hollow nanostructures with tunable porosity and chemical composition, leading to tailored optical and catalytic properties. However, the precise interplay between the three-dimensional (3D) morphology and chemical composition of nanostructures during galvanic replacement is not always well understood as the 3D chemical imaging of nanoscale materials is still challenging. It is especially far from straightforward to obtain detailed information from the inside of hollow nanostructures using electron microscopy techniques such as SEM or TEM. We demonstrate here that a combination of state-of-the-art EDX mapping with electron tomography results in the unambiguous determination of both morphology transformation and elemental composition of nanostructures in 3D, during galvanic replacement of Ag nanocubes. This work provides direct and unambiguous experimental evidence toward understanding the galvanic replacement reaction. In addition, the powerful approach presented here can be applied to a wide range of nanoscale transformation processes, which will undoubtedly guide the development of novel nanostructures.
Collapse
Affiliation(s)
- Bart Goris
- EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020, Antwerp, Belgium
| | | | | | | | | |
Collapse
|
20
|
Boneschanscher MP, Evers WH, Geuchies JJ, Altantzis T, Goris B, Rabouw FT, van Rossum SAP, van der Zant HSJ, Siebbeles LDA, Van Tendeloo G, Swart I, Hilhorst J, Petukhov AV, Bals S, Vanmaekelbergh D. Long-range orientation and atomic attachment of nanocrystals in 2D honeycomb superlattices. Science 2014; 344:1377-80. [DOI: 10.1126/science.1252642] [Citation(s) in RCA: 316] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
|
21
|
Goris B, De Backer A, Van Aert S, Gómez-Graña S, Liz-Marzán LM, Van Tendeloo G, Bals S. Three-dimensional elemental mapping at the atomic scale in bimetallic nanocrystals. Nano Lett 2013; 13:4236-41. [PMID: 23952010 DOI: 10.1021/nl401945b] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A thorough understanding of the three-dimensional (3D) atomic structure and composition of core-shell nanostructures is indispensable to obtain a deeper insight on their physical behavior. Such 3D information can be reconstructed from two-dimensional (2D) projection images using electron tomography. Recently, different electron tomography techniques have enabled the 3D characterization of a variety of nanostructures down to the atomic level. However, these methods have all focused on the investigation of nanomaterials containing only one type of chemical element. Here, we combine statistical parameter estimation theory with compressive sensing based tomography to determine the positions and atom type of each atom in heteronanostructures. The approach is applied here to investigate the interface in core-shell Au@Ag nanorods but it is of great interest in the investigation of a broad range of nanostructures.
Collapse
Affiliation(s)
- Bart Goris
- Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | | | | | | | | | | | | |
Collapse
|
22
|
Evers WH, Goris B, Bals S, Casavola M, de Graaf J, van Roij R, Dijkstra M, Vanmaekelbergh D. Low-dimensional semiconductor superlattices formed by geometric control over nanocrystal attachment. Nano Lett 2013; 13:2317-23. [PMID: 23050516 DOI: 10.1021/nl303322k] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Oriented attachment, the process in which nanometer-sized crystals fuse by atomic bonding of specific crystal facets, is expected to be more difficult to control than nanocrystal self-assembly that is driven by entropic factors or weak van der Waals attractions. Here, we present a study of oriented attachment of PbSe nanocrystals that counteract this tuition. The reaction was studied in a thin film of the suspension casted on an immiscible liquid at a given temperature. We report that attachment can be controlled such that it occurs with one type of facets exclusively. By control of the temperature and particle concentration we obtain one- or two-dimensional PbSe single crystals, the latter with a honeycomb or square superimposed periodicity in the nanometer range. We demonstrate the ability to convert these PbSe superstructures into other semiconductor compounds with the preservation of crystallinity and geometry.
Collapse
Affiliation(s)
- Wiel H Evers
- Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 1, P.O. Box 80.000, 3508 TA, Utrecht, The Netherlands
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Schouteden K, Zeng YJ, Lauwaet K, Romero CP, Goris B, Bals S, Van Tendeloo G, Lievens P, Van Haesendonck C. Band structure quantization in nanometer sized ZnO clusters. Nanoscale 2013; 5:3757-3763. [PMID: 23515535 DOI: 10.1039/c3nr33989k] [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
Nanometer sized ZnO clusters are produced in the gas phase and subsequently deposited on clean Au(111) surfaces under ultra-high vacuum conditions. The zinc blende atomic structure of the approximately spherical ZnO clusters is resolved by high resolution scanning transmission electron microscopy. The large band gap and weak n-type conductivity of individual clusters are determined by scanning tunnelling microscopy and spectroscopy at cryogenic temperatures. The conduction band is found to exhibit clear quantization into discrete energy levels, which can be related to finite-size effects reflecting the zero-dimensional confinement. Our findings illustrate that gas phase cluster production may provide unique possibilities for the controlled fabrication of high purity quantum dots and heterostructures that can be size selected prior to deposition on the desired substrate under controlled ultra-high vacuum conditions.
Collapse
Affiliation(s)
- Koen Schouteden
- Laboratory of Solid-State Physics and Magnetism, KU Leuven, Celestijnenlaan 200d-box 2414, BE-3001 Leuven, Belgium.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Goris B, Roelandts T, Batenburg K, Heidari Mezerji H, Bals S. Advanced reconstruction algorithms for electron tomography: From comparison to combination. Ultramicroscopy 2013; 127:40-7. [DOI: 10.1016/j.ultramic.2012.07.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
25
|
Sánchez-Iglesias A, Grzelczak M, Altantzis T, Goris B, Pérez-Juste J, Bals S, Van Tendeloo G, Donaldson SH, Chmelka BF, Israelachvili JN, Liz-Marzán LM. Hydrophobic interactions modulate self-assembly of nanoparticles. ACS Nano 2012; 6:11059-11065. [PMID: 23186074 DOI: 10.1021/nn3047605] [Citation(s) in RCA: 244] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Hydrophobic interactions constitute one of the most important types of nonspecific interactions in biological systems, which emerge when water molecules rearrange as two hydrophobic species come close to each other. The prediction of hydrophobic interactions at the level of nanoparticles (Brownian objects) remains challenging because of uncontrolled diffusive motion of the particles. We describe here a general methodology for solvent-induced, reversible self-assembly of gold nanoparticles into 3D clusters with well-controlled sizes. A theoretical description of the process confirmed that hydrophobic interactions are the main driving force behind nanoparticle aggregation.
Collapse
Affiliation(s)
- Ana Sánchez-Iglesias
- Bionanoplasmonics Laboratory, CIC biomaGUNE, Paseo de Miramón 182, 20009 Donostia, San Sebastián, Spain
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Goris B, Bals S, Van den Broek W, Carbó-Argibay E, Gómez-Graña S, Liz-Marzán LM, Van Tendeloo G. Atomic-scale determination of surface facets in gold nanorods. Nat Mater 2012; 11:930-5. [PMID: 23085569 DOI: 10.1038/nmat3462] [Citation(s) in RCA: 183] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 09/17/2012] [Indexed: 05/19/2023]
Abstract
It is widely accepted that the physical properties of nanostructures depend on the type of surface facets. For Au nanorods, the surface facets have a major influence on crucial effects such as reactivity and ligand adsorption and there has been controversy regarding facet indexing. Aberration-corrected electron microscopy is the ideal technique to study the atomic structure of nanomaterials. However, these images correspond to two-dimensional (2D) projections of 3D nano-objects, leading to an incomplete characterization. Recently, much progress was achieved in the field of atomic-resolution electron tomography, but it is still far from being a routinely used technique. Here we propose a methodology to measure the 3D atomic structure of free-standing nanoparticles, which we apply to characterize the surface facets of Au nanorods. This methodology is applicable to a broad range of nanocrystals, leading to unique insights concerning the connection between the structure and properties of nanostructures.
Collapse
Affiliation(s)
- Bart Goris
- Electron Microscopy for Materials Research (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
| | | | | | | | | | | | | |
Collapse
|
27
|
Van den Broek W, Rosenauer A, Goris B, Martinez G, Bals S, Van Aert S, Van Dyck D. Correction of non-linear thickness effects in HAADF STEM electron tomography. Ultramicroscopy 2012. [DOI: 10.1016/j.ultramic.2012.03.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
28
|
Goris B, Huis MAV, Bals S, Zandbergen HW, Manna L, Tendeloo GV. Thermally induced structural and morphological changes of CdSe/CdS octapods. Small 2012; 8:937-42. [PMID: 22290792 DOI: 10.1002/smll.201101897] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Indexed: 05/08/2023]
Abstract
Branched nanostructures are of great interest because of their promising optical and electronic properties. For successful and reliable integration in applications such as photovoltaic devices, the thermal stability of the nanostructures is of major importance. Here the different domains (CdSe cores, CdS pods) of the heterogeneous octapods are shown to have different thermal stabilities, and heating is shown to induce specific shape changes. The octapods are heated from room temperature to 700 °C, and investigated using (analytical and tomographic) transmission electron microscopy (TEM). At low annealing temperatures, pure Cd segregates in droplets at the outside of the octapods, indicating non-stochiometric composition of the octapods. Furthermore, the tips of the pods lose their faceting and become rounded. Further heating to temperatures just below the sublimation temperature induces growth of the zinc blende core at the expense of the wurtzite pods. At higher temperatures, (500-700 °C), sublimation of the octapods is observed in real time in the TEM. Three-dimensional tomographic reconstructions reveal that the four pods pointing into the vacuum have a lower thermal stability than the four pods that are in contact with the support.
Collapse
Affiliation(s)
- Bart Goris
- EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | | | | | | | | | | |
Collapse
|
29
|
Justo Y, Goris B, Kamal JS, Geiregat P, Bals S, Hens Z. Multiple Dot-in-Rod PbS/CdS Heterostructures with High Photoluminescence Quantum Yield in the Near-Infrared. J Am Chem Soc 2012; 134:5484-7. [DOI: 10.1021/ja300337d] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - Bart Goris
- EMAT, University of Antwerp, B-2020 Antwerp, Belgium
| | | | | | - Sara Bals
- EMAT, University of Antwerp, B-2020 Antwerp, Belgium
| | | |
Collapse
|
30
|
Goris B, Bals S, Van den Broek W, Verbeeck J, Van Tendeloo G. Exploring different inelastic projection mechanisms for electron tomography. Ultramicroscopy 2011; 111:1262-7. [PMID: 21864766 DOI: 10.1016/j.ultramic.2011.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 02/10/2011] [Accepted: 02/22/2011] [Indexed: 11/18/2022]
Abstract
Several different projection mechanisms that all make use of inelastically scattered electrons are used for electron tomography. The advantages and the disadvantages of these methods are compared to HAADF-STEM tomography, which is considered as the standard electron tomography technique in materials science. The different inelastic setups used are energy filtered transmission electron microscopy (EFTEM), thickness mapping based on the log-ratio method and bulk plasmon mapping. We present a comparison that can be used to select the best inelastic signal for tomography, depending on different parameters such as the beam stability and nature of the sample. The appropriate signal will obviously also depend on the exact information which is requested.
Collapse
Affiliation(s)
- B Goris
- EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
| | | | | | | | | |
Collapse
|
31
|
Li Y, Tan H, Yang XY, Goris B, Verbeeck J, Bals S, Colson P, Cloots R, Van Tendeloo G, Su BL. Well shaped Mn₃O₄ nano-octahedra with anomalous magnetic behavior and enhanced photodecomposition properties. Small 2011; 7:475-83. [PMID: 21254396 DOI: 10.1002/smll.201001403] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Indexed: 05/25/2023]
Abstract
Very uniform and well shaped Mn₃O₄ nano-octahedra are synthesized using a simple hydrothermal method under the help of polyethylene glycol (PEG200) as a reductant and shape-directing agent. The nano-octahedra formation mechanism is monitored. The shape and crystal orientation of the nanoparticles is reconstructed by scanning electron microscopy and electron tomography, which reveals that the nano-octahedra only selectively expose {101} facets at the external surfaces. The magnetic testing demonstrates that the Mn₃O₄ nano-octahedra exhibit anomalous magnetic properties: the Mn₃O₄ nano-octahedra around 150 nm show a similar Curie temperature and blocking temperature to Mn₃O₄ nanoparticles with 10 nm size because of the vertical axis of [001] plane and the exposed {101} facets. With these Mn₃O₄ nano-octahedra as a catalyst, the photodecomposition of rhodamine B is evaluated and it is found that the photodecomposition activity of Mn₃O₄ nano-octahedra is much superior to that of commercial Mn₃O₄ powders. The anomalous magnetic properties and high superior photodecomposition activity of well shaped Mn₃O₄ nano-octahedra should be related to the special shape of the nanoparticles and the abundantly exposed {101} facets at the external surfaces. Therefore, the shape preference can largely broaden the application of the Mn₃O₄ nano-octahedra.
Collapse
Affiliation(s)
- Yu Li
- State Key Laboratory of Advanced Technology for Materials, Synthesis and Processing, Wuhan University of Technology, 122 LuoShi Road, Wuhan, Hubei, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|