Heteroepitaxy of Organic Nanofibers: Example of Ternaphthalene on p-Hexaphenyl

Abstract

Nowadays heteroepitaxy is well understood and investigated for inorganic compounds. In contrast, the epitaxial growth of organic–organic multilayer structures is rarely reported. By a comprehensive comparison between experiments and simulations, we demonstrate that highly anisotropic, needle-shaped p-hexaphenyl (p-6P) crystallites can efficiently act as an organic template and that the epitaxial overgrowth by 2,2′:6′,2″-ternaphthalene (NNN) yields a high molecular order and optical anisotropy of the nucleated NNN crystallites. It is shown that surface corrugations formed by the p-6P template are responsible for a parallel molecular alignment and a geometrical adoption of the herringbone stacking sequence of NNN. On the basis of the obtained results, it can be concluded that, in contrast to inorganic heteroepitaxy, lattice matching plays a minor role, whereas a geometrical adoption of the molecular stacking is directly connected with an optimized adsorption energy. In that sense, polarization-dependent pho...