Highly Luminescent Europium(III) Complexes in Solution and PMMA-Doped Films for Bright Red Electroluminescent Devices.

This paper reports the synthesis, structure, photophysical, and optoelectronic properties of five eight-coordinate Europium(III) ternary complexes, namely, [Eu(hth)(L)], bearing 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione (hth) as a sensitizer and L = HO (), dpso (diphenyl sulphoxide, ), dpsoCH (4,4'-dimethyl diphenyl sulfoxide, ), dpsoCl (bis(4-chlorophenyl)sulphoxide, ), and tppo (triphenylphosphine oxide, ) as co-ligands. The NMR and the crystal structure analysis confirmed the eight-coordinate structures of the complexes in solution and in a solid state. Upon UV-excitation on the absorption band of the β-diketonate ligand hth, all complexes showed the characteristic bright red luminescence of the Europium ion. The tppo derivative () displayed the highest quantum yield (up to 66%). As a result, an organic light-emitting device, OLED, was fabricated with a multi-layered structure-ITO/MoO/mCP/SF3PO:[complex ] (10%)/TPBi:[complex ] (10%)/TmPyPB/LiF/Al-using complex as the emitting component.