Nanoparticle Self-Assemblies

Nanoparticle  Self-Assemblies. Mesocrystals

 Mesocrystals  are nanostructured materials characterized by a defined order on the atomic scale (which can be inferred from the existence of an essentially sharp wide angle diffraction pattern) together with clear evidence that the material consists of individual nanosized building units. In the past years, we have structurally characterized a large variety of inorganic-organic nanocomposite materials incl. biological and biomimetic materials as well as nanoparticle self-assemblies. The self-assembly of monodisperse anisotropic nanocrystals (stabilized by organic molecules) allows to generate a special type of mesocrytals which fulfils the criteria of crystalline material on two length scales: ordered superlattice (colloidal crystal) together with specific crystallographic orientation of the crystalline building blocks. One of our recent examples is the detailed structural characterization of 2D and 3D mesocrystaline materials based on iron oxide nanoparticle self-assemblies. The approach we are using in our study aims to determine the orientational relations between the nanocrystals within the superlattice and also to develop atomistic models suitable for a detailed description of the structures of the colloidal superlattices (mesocrystals). Furthermore, we are also examining the effect of synthesis conditions on the self-assembly process and especially on the formation of 3D faceted mesocrystals.