Photo- and electroluminescent properties europium complexes using bistriazole ligands

Luminescent properties of two heteroleptic dibenzoylmethanate europium(III) complexes with 1,3-bis(5-pyridin-2-yl-1,2,4-triazol-3-yl)propane (H 2 L 1 ) and 1,4-bis(5-pyridin-2-yl-1,2,4-triazol-3-yl)butane (H 2 L 2 ) as ancillary ligands are described. The two double-layer-type electroluminescent cells with the structures: (1) ITO/NPB(40 nm)/Eu(DBM) 2 HL 1 (40 nm)/LiF (1 nm)/Al (100 nm) and (2) ITO/NPB(40 nm)/Eu(DBM) 2 HL 2 (40 nm)/LiF (1 nm)/Al (100 nm) emit red light originating from the europium complexes. The device 2 gives the maximum brightness of 455 cd/m 2 at 19.2 V.