Oxide ancillary ligand-based europium β-diketonate complexes and their enhanced luminosity

Abstract

Ternary materials of europium complex with 2,2,6,6-tetramethyl-3,5-heptanedione (tmhd) ligand and aqua ligand as ancillary ligands have been prepared and characterized for various optoelectronic characteristics. Reactions of hydrated complex [Eu(tmhd)3(H2O)2] proceeded with triphenylphosphine oxide (TPPO) and pyridine-N-oxide (PNO) ancillary ligands were studied to develop novel complexes. The prepared complexes show good thermal stability. A comparative investigation of prepared materials [Eu(tmhd)3(H2O)2], [Eu(tmhd)3(TPPO)2] and [Eu(tmhd)3(PNO)2] was conducted for their luminescent behaviors in order to obtain the role of ancillary ligand in the enhancement of illumination amount generated from europium (Eu3+) ion. Color coordinates of prepared ternary complexes such as [Eu(tmhd)3(H2O)2] with (x = 0.54, y = 0.32), [Eu(tmhd)3(TPPO)2] with (x = 0.56, y = 0.32) and [Eu(tmhd)3(PNO)2] with (x = 0.57, y = 0.33) indicated that these materials exhibited bright red emission in visible region spectrum. The complexes show a proficient energy transport pathway from the ligands to the innermost Eu3+ by means of an ancillary ligand-sensitized luminescence process. Interaction between the metal and ligand results in a distinguished effect on quantum efficiency (η) as well as on Judd–Ofelt intensity factor (Ω2) of the prepared materials.