Synthesis, crystallography, photoluminescence and electroluminescence of three polymorphs of dibenzoylmethane gallium complex

Three polymorphs of tris(dibenzoylmethane) gallium were characterized by optical microscopy, absorption, photoluminescence (PL) and used for electroluminescent devices (EL). PL spectrum of the thin film is composed of both gamma-type yellow emission and beta-type blue emission, but only gamma-type yellow EL emission was observed, indicating the polymorphic counterpart beta-type with weaker pi-pi interactions was defeated in competition for EL generation. A comparison of the three polymorphic crystal structures reveals that a zigzag channel from intermolecular pi-pi interaction at a distance of 3.6-3.7 angstrom to intramolecular bond-bond conjugation may dominate the charge transport and be responsible for the yellow EL emission. (c) 2006 Elsevier B.V. All rights reserved.Chemistry, Inorganic & NuclearSCI(E)4ARTICLE51593-159836