Abstract

In materials chemistry, one uses the term soft-chemistry to differentiate mild preparation approaches (e.g. sol-gel) from the harsh conditions necessary in classical solid-state methods. The advantage is, one can access metastable states, most importantly all sorts of different nanostructures. A very powerful strategy is to use so-called single-source precursors, molecules which contain all elements necessary for the formation of the desired materials. The presentation will highlight three different types of semiconductors: ZnO,1-5 EuO6-7 and CH3NH3 PbX3.8-12 We are in particular interested in shape-property correlations. Such correlations are expected to exist, because the shape of a crystal in general can be defined by a variation of the abundance of certain crystal facets and, for nanoparticles, the surface to volume ratio is high. The presentation will give examples on possibilities and limits in controlling nanoparticle shape. Examples for effects on optical, electronic and magnetic properties in doped and undoped nanoparticles. The influence of shape factors for their self-assembly will be discussed, which is an important issue for future particle-based materials.