Abstract
Fabrication and electroluminescent properties of devices containing europium complexes of general formula [Eu(ACIND) 3(TPPO) 2], where ACIND, 2-acyl-1,3-indandionate ligands; and TPPO, triphenylphosphine oxide, as emitter layers are discussed. The double-layer devices based on these complexes present the following configurations: device 1: ITO/TPD/[Eu(AIND) 3(TPPO) 2]/Al; device 2: ITO/TPD/[Eu(ISOVIND) 3(TPPO) 2]/Al and device 3: ITO/TPD/[Eu(BIND) 3(TPPO) 2]/Al, where AIND, 2-acetyl-1,3-indandionate; ISOVIND, 2-isovaleryl-1,3-indandionate; and BIND, 2-benzoyl-1,3-indandionate, respectively. These devices exhibited photo and electroluminescent emissions. An important characteristic presented by devices is that their electroluminescent (EL) spectra, in the region of 5D 0 → 7F J ( J = 0, 1, 2, 3 and 4) transitions of Eu 3+ ion, show profiles that are different from photoluminescent (PL) ones. In addition to narrow bands arising from intraconfigurational-4f 6 transitions, devices 1 and 2 also exhibited a broad band with maximum at around 500 nm which is assigned to electrophosphorescence from the indandionate ligands. On the other hand, EL spectra of device 3 present only narrow bands from 5D 0 → 7F J transitions. [Eu(ACIND) 3(TPPO) 2] complexes are promising candidates to prepare efficient organic light-emitting devices (OLEDs) when compared with those containing Eu 3+-complexes of aliphatic β-diketonate anions.
Published Version
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