3D Nanometrology

Work-Package 23

In 2001, Paul Midgley and co-workers demonstrated the potential of electron tomography in materials science based on high angle annular dark field scanning transmission electron microscopy. Since then, different electron microscopy modes have been combined successfully with tomography, leading to a broad variety of 3D structural and compositional information at the nanoscale. In this Work Package, we aim to obtain precise and quantitative measurements of structures, morphologies and properties in 3D, in some cases at the atomic scale in order to provide a better suite of methods that can be applied by academic and industrial users.

An exciting example of the progress that was made in this WP so far concerns high-resolution electron tomography. Being able to visualize atoms in 3D has been a dream for many years. In this WP, atomic resolution electron tomography was achieved by using “compressive sensing” [1]. The technique was applied to Au nanorods and the result is presented in Figure 1.a. The atom positions are not fixed during the 3D reconstruction, meaning that the reconstruction can serve as a starting point for many other investigations such as ab-initio calculations or strainmeasurements (Figure 1.b). The results discussed above were obtained at the University of Antwerp and currently, different partners in the JRA are not only comparing different approaches to obtain 3D results at the atomic scale, also novel synergistic approaches to determine the position and chemical nature of each atom in a nanomaterial are being developed. Such measurements will enable researchers to understand and optimize the synthesis of complex nanostructures.

JRA4 - image 1

Figure 1: a) Three orthogonal slices through the reconstruction of a Au nanorod, showing individual atom positions. The facets composing the morphology can be determined.
b) Slices through the 3D εzz strain measurement indicate an outward relaxation of the atoms at the tip of the nanorod.

 

Another goal of the WP is to extend current electron tomography approaches to the measurements of materials properties such as electromagnetic fields or optical properties. Different collaborations between the partners have been initiated on this topic, but a highlight in this WP is definitely the recent publication by the University of
Cambridge in Nature [2]. In this publication, a 3D reconstruction of local ised surface plasmon resonances was obtained for a Ag nanoparticle (see Figure 2) by combining state-of-the-art electron microscopy with advanced computational techniques. These measurements will enable one to obtain a better understanding of the optical properties of nanomaterials.

JRA4 - image 2

Figure 2: This figure visualizes the different localized surface plasmon modes of a Ag nanoparticle in 3D.

 

During the remainder of the project, one of our goals will be to combine electron tomography measurements with in-situ experiments. This will enable us to investigate how morphology and properties of nanoparticles change under conditions such as heating or application of fields. We expect that extending electron tomography to dynamical processes and investigation of nanoparticle dynamics will have great impact in the field of catalysis and optoelectronics.

[1] B. Goris, S. Bals, W. Van den Broek, E. Carbó-Argibay, S. Gómez-Graña, L.M. Liz-Marzán, G. Van Tendeloo, Atomic scale determination of surface facets in gold nanorods, Nature Materials 11 (2012) 930–935

[2] O. Nicoletti, F. de la Peña, R. K. Leary, D. J. Holland, C. Ducati, P. A. Midgley, Three-dimensional imaging of localized surface plasmon resonances of metal nanoparticles, Nature 502 (2013) 80-84

 

Deliverable: Progress report on high resolution 3D reconstruction

Partners involved:

Universiteit Antwerpen (Work-Package leader); CNRS/CEMES (WP co-leader); University of Oxford; University of Cambridge; ER-C  Jülich; Chalmers TH; Universidad de Cadiz; AGH Krakow; TU Dresden

Contacts:

Sara Bals (Universiteit Antwerpen)
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Martin Hÿtch (CNRS/CEMES Toulouse) 
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