J. Ackermann

Competing Forces in the Self-Assembly of Coupled ZnO Nanopyramids

Self-assembly (SA) of nanostructures has recently gained increasing interest. A clear understanding of the process is not straightforward since SA of nanoparticles is a complex multiscale phenomenon including different driving forces. Here, we study the SA between aluminum doped ZnO nanopyramids into couples by combining inorganic chemistry and advanced electron microscopy techniques with atomistic simulations. Our results show that the SA of the coupled nanopyramids is controlled first by morphology, as coupling only occurs in the case of pyramids with well-developed facets of the basal planes. The combination of electron microscopy and atomistic modeling reveals that the coupling is further driven by strong ligand-ligand interaction between the bases of the pyramids as dominant force, while screening effects due to Al doping or solvent as well as core-core interaction are only minor contributions. Our combined approach provides a deeper understanding of the complex interplay between the interactions at work in the coupled SA of ZnO nanopyramids.

Epitaxial Relationships of Vapor Deposited Thin Films of Octithiophene on KBr (001)

ABSTRACT The epitaxial relationships of vapor deposited thin films of octithiophene onto KBr (001) were investigated by X-ray diffractometry. The temperature dependence of the film structure was examined between 25°C and 125°C. Two kinds of orientations, standing (100) and lying (51 − 1), were observed and the former orientation preferentially occurred at higher temperatures. The epitaxial relationships of both standing and lying orientations were determined. The observed epitaxial relationships were explained in terms of misfit ratio.