EUROPIUM COMPLEXES AS EMITTERS IN ORGANIC ELECTROLUMINESCENT DEVICES

Using two different trivalent europium (Eu3+) complexes, ropium(dibenz oylmethanato)(3)(bathophenanthroline) [Eu(DBM)(3)bath] and uropium(dib enzoylmethanato)(3)(monophenanthroline) [Eu(DBM)(3)phen], with differe nt ligands for emission-layer materials, various types of electrolumin escent (EL) devices have been fabricated. Combined with a triphenylami ne derivative (TPD) and an oxadiazole derivative (OXD7) as hole-transp ort-layer materials, two-layer-and three-layer-type devices have been fabricated. We find that these two emission-layer materials have simil ar EL spectra, but their EL performances are different. The EL capabil ity of the Eu complexes and their carrier-transporting characteristics are largely dependent on the ligands. (C) 1997 Elsevier Science S.A.