Synthesis and morphology of iron-iron oxide core-shell nanoparticles produced by high pressure gas condensation.

Core-shell structured Fe nanoparticles (NPs) produced by high pressure magnetron sputtering gas condensation were studied using transmission electron microscopy (TEM) techniques, electron diffraction, electron energy-loss spectroscopy (EELS), tomographic reconstruction, and Wulff shape construction analysis. The core-shell structure, which is composed of an Fe core surrounded by a maghemite (γ-Fe2O3) and/or magnetite (Fe3O4) shell, was confirmed by fast Fourier transform (FFT) analysis combined with EELS. It was found that the particle size and shape strongly depend on the gas environment.

Correlated 3D Nanoscale Mapping and Simulation of Coupled Plasmonic Nanoparticles.

Electron tomography in combination with electron energy-loss spectroscopy (EELS) experiments and simulations was used to unravel the interplay between structure and plasmonic properties of a silver nanocuboid dimer. The precise 3D geometry of the particles fabricated by means of electron beam lithography was reconstructed through electron tomography, and the full three-dimensional information was used as an input for simulations of energy-loss spectra and plasmon resonance maps. Excellent agreement between experiment and theory was found throughout, bringing the comparison between EELS imaging and simulations to a quantitative and correlative level.

Morphing a plasmonic nanodisk into a nanotriangle.

We morph a silver nanodisk into a nanotriangle by producing a series of nanoparticles with electron beam lithography. Using electron energy loss spectroscopy (EELS), we map out the plasmonic eigenmodes and trace the evolution of edge and film modes during morphing. Our results suggest that disk modes, characterized by angular order, can serve as a suitable basis for other nanoparticle geometries and are subject to resonance energy shifts and splittings, as well as to hybridization upon morphing.

In situ determination and imaging of physical properties of soft organic materials by analytical transmission electron microscopy.

Analytical transmission electron microscopy (ATEM) offers great flexibility in identification of the structural-chemical organization of soft materials at the level of individual macromolecules. However, the determination of mechanical characteristics such as hardness/elasticity of the amorphous and polycrystalline organic substances by ATEM has been problematic so far. Here, we show that energy filtered TEM (EFTEM) measurements enable direct identification and study of mechanical properties in complex (bio-)polymer systems of relevance for different industrial and (bio-)medical applications.