Red to near-infrared electrophosphorescence from an iridium complex coordinated with 2-phenylpyridine and 8-hydroxyquinoline

An iridium complex coordinated with 2-phenylpyridine (ppy) and 8-hydroxyquinoline (q), ppy(2)Irq, was synthesized and its thermal stability, absorption. photoluminescence, crystal structure and electrophosphorescence were characterized. The melting point of this material reaches as high as 374 degrees C and does not suffer decomposition upon heating at high vacuum therefore can be well sublimated. When PPY(2)Irq was used as a guest emitting material in the electrophosphorescent device, the emission is 100% saturated red light starting at similar to 600 nm. extending into the near-infrared region. The bathochromic shift, compared to the fluorescence and phosphorescence from Alq(3), Ptq(2), and Ir(ppy)(3), was analyzed to originate from the triplet excited state of 8-hydroxyquinoline ligand and the crystal structure analysis excludes the origin of pi-pi intermolecular interactions. (c) 2007 Elsevier B.V. All rights reserved.