Photo- and electro-luminescence studies of a new nine-coordinate ternary Eu(III) complex

A new 4′-(3,4-dimethoxyphenyl)-2,2′:6′,2″-terpyridine (DmP-TerPy) ligand has been synthesized and utilized as the ancillary ligand in conjunction with the primary antenna ligand 4,4,4-trifluoro-1-phenyl-1,3-butanedione (btfa) to develop a new nine coordinate red emitting ternary Eu(III) complex, [Eu(btfa)₃(DmP-TerPy] (Eu1). Eu1 was characterised by analytical and spectroscopic techniques and its photophysical properties were analysed. The experimental results were complemented by computational methods, namely, density functional theory (DFT), time-dependent density functional theory (TD-DFT), and the Lanthanide Luminescence Software Package (LUMPAC), to establish the photoluminescence (PL) properties of the sensitised Eu(III) complex and the energy transfer (EnT) processes involved. Finally, to test the application of Eu1 as a narrow band red emitter, the material was used as the emitting layer (EML) in a multi-layered host-guest device to fabricate highly monochromatic red organic light-emitting diodes (R-OLED).