White light emissive bipolar ligand and their EuIII complex for white/red light emitting diodes

Fluorene integrated phenanthro-imidazole (phenyl factionalized) bipolar ligand and their corresponding Eum complex was successfully synthesized and studied their photophysical properties. The newly synthesized ligand shown strong absorption in the near UV region and emit white light by covering the whole visible region (400-700 nm). The corresponding Eu-complex (Eu(TTA)(3)Phen-Fl-Ph) shown red emission with strong electric dipole transition at 612 nm (D-5(0) -> F-7(2)). Efficient energy transfer from ligand to Eu metal ion was confirmed by combined experimental and time-dependent density functional theory (TD-DFT). The absolute quantum yield (QY) of the complex found to be 57.3 (0.5%) in PMMA matrix. The ligand integrated with InGaN LED chip (395 nm, forward bias 20 mA) shown the potentiality of the ligand and displayed white emission. Whereas, the Eu-complex conjugated LED was shown red emission. The obtained results are indicating that the currently synthesized ligand and the complex were potential to be used as single molecular white emission and red emitting component LEDs, respectively. (C) 2017 Published by Elsevier B.V.