Photophysical studies on ternary mixed ligand europium complexes containing pyridyltriazolylmethane and 1,3-diketonate ligands

1,1-Bis[5-(pyridine-2-yl)-1,2,4-triazol-3-yl]methane have been used to prepare ternary lanthanide complexes in which the remaining ligands are different diketonate-anions. The complexes were characterized by various measurements including single-crystal X-ray crystallography. The characteristic photophysical properties of these complexes, i.e. the absorption and luminescence spectra, the metal-centred lifetimes and the overall luminescence yields were measured. All title complexes show strong sharp red emissions in the solid state, corresponding to 5D0 → 7FJ (J = 0–3) transitions with 5D0 → 7F2 (612–621 nm) as the most prominent one. Three-layer light-emitting diodes based on PVK doped with the title complexes as active layer were fabricated and examined.