Atomic scale structure of amorphous aluminum oxyhydroxide, oxide and oxycarbide films probed by very high field 27Al nuclear magnetic resonance

The atomic scale structure of aluminum in amorphous alumina films processed by direct liquid injection chemical vapor deposition from aluminum tri-isopropoxide (ATI) and dimethyl isopropoxide (DMAI) is investigated by solid-state 27Al nuclear magnetic resonance at 20 T.

Characterization of Isomers in Solid Aluminum tris-(Quinoline-8-olate) by 27Al NMR

Aluminum tris-(quinoline-8-olate) (Alq3) is the most widely used electron transport material for organic light emitting diodes. The Alq3 molecule exists as two different isomers: meridianal and facial, which differ by the symmetry of the arrangement of ligands around the aluminum ion. Various crystalline polymorphs of Alq3 have been identified to contain one of these isomers. In this paper we present experimental results that show that the facial and meridianal isomers of Alq3 can be distinguished in the solid state by 27Al nuclear magnetic resonance (NMR) spectroscopy under magic angle spinning (MAS). Our results prove that the recently discovered δ-phase of Alq3 exclusively contains the facial isomer. The same technique is also used to characterize the amorphous deposit of Alq3 showing that it is the meridianal isomer that predominantly exists in the amorphous state.