Thin films of perfectly polar crystallites with uniaxial orientational ordering

Abstract

The family of metal-organic complexes,(4-dialkylaminopyridyl)bis(acetylacetonato)zinc(II) which show perfectly polar assembly in the crystalline state are found to grow as orientationally ordered crystallites in vapor deposited thin films on glass substrates. A unique crystallographic axis of the crystallites, the longest unit cell axis in most cases, is oriented perpendicular to the substrate plane. The fact that the current observations cover a family of compounds is novel and of general significance for oriented thin film growth on amorphous substrates. Crystal structure, thin film morphology and second harmonic generation of a representative system are presented; the crystallites in the thin films do not show azimuthal orientational ordering.