Synthesis, structures and spectroscopy of three new lanthanide f3-diketonate complexes with 4,4 '-dimethy1-2,2 '-bipyridine. Near-infrared electroluminescence of ytterbium(III) complex in OLED

摘要

Three new lanthanide(III) beta-diketonate complexes (Ln(byfa)(3) (4,4'-dmbpy)] (Ln = Yb(III), Gd(III) and Nd(III); btfa = anionic 4,4,4-trifluoro-l-phenyl-1,3-butanedione and 4,4'-drnbpy = 4,4'-dimethy1-2,2'-bipyridine) were synthesized and their characterization, including elemental analysis, FTIR spectroscopy and thermal analysis (TG/DTA), is reported. The crystal description based on powder X-ray diffraction reveals that Gd(III) and Yb(III) compounds are isostructural and that lanthanide ion is eight-coordinated by oxygen and nitrogen atoms to give new Iris-beta-diketonates (Ln(byfa) 3 (4,4'-dmbpy)]. The cell parameters of Nd(III) complex are close to Gd(III) and Yb(III) ones. Phosphorescence data of Gd(III) complex shows that the triplet states (T-1) of the ligands have higher energy than the emitting states of Yb(III) and Nd(III), indicating the possibility of intramolecular energy transfer to these metal ions, which exhibit near-infrared (NIR) emission. We have used the Yb(III) complex as an emitting layer (EML) in a near infrared organic light emitting diode (NIR-OLED) with the structure: CuPc (15 nm)/XD-03(40 nm)/Yb(60 nm)/BCP(15 nm)/Alq(3) (10 nm)/Al(120 nm). OLEDs exhibit both visible electroluminescence and a NIR electroluminescence at 980 nm from the F-2(5/2) - F-2(7/2) transition of the Yb(III).