Materialien

Rechargeable Lithium-ion batteries play an indispensable role in our daily lives. They power everything from cell phones to computers and even cars. We are working on understanding the fundamental science behind them in order to make them better. In particular, we are interested in the structural and chemical mechanisms of the Li-ion insertion and excertion into the nanomaterials that make up the batteries electrodes.

Hexagonal boron nitride (h-BN) is a layered material that structurally closely resembles graphite. It has long been known as a wide band-gap material with outstanding mechanical, electrical and optical properties. It consists of a layered structure that is very similar to graphite. Recently, we have achieved to fabricate free-hanging single layer hexagonal boron nitride membranes and detect individual boron and nitrogen atoms by aberration-corrected transmission electron microscopy. This new material can be considered the insulating equivalent of graphene.

Graphene is currently one of the hottest research topics in nanotechnology. Our group studies naturally occurring and irradiation induced defects in graphene, graphene edges, and graphene ribbons by atomic resolution TEM imaging. In addition, we also investigate the use of graphene as an ideal substrate for high resolution TEM studies of other materials.

Magnetic nanoparticles and thin films have attracted enormous attention over the last years due to their potential use in magnetic data storage or sensing applications. Among them, micellar FePt alloy nanoparticles and films exhibiting particularly large magnetic anisotropy energy densities (MAE). Analytical transmission electron microscopy is essential for characterization of these nanoparticles.

Almost all modern optical devices rely on the leverage effect of optical coatings. These are fabricated by film growth, a unique low-cost nanofabrication process. Only, for controlling the optical properties of these films it is essential to know its real structure on the atomic scale. Our TEM studies of coatings provide a tool for understanding and optimisation of growth parameters.