Designing and Judd-Ofelt evaluation of versatile luminescent Eu (III) complexes sensitized with β-diketone ligand for multifarious applications.

The present research work entails the synthesis of one binary and four ternary red light-emitting Eu (III)-based complexes with 3-benzylidene-2,4-pentanedione as the main ligand and 1,10-phenanthroline, bathophenanthroline, neocuproine, and 4,4'-'dimethyl-2,2'-'bipyridyl as auxiliary ligands. The metal-organic framework of the series was elucidated using energy dispersive X-ray analysis, elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance. This Eu (III) series exhibits optimum thermal stability, making them a promising candidate for organic light-emitting diodes. On the basis of emission spectra, their optical parameters such as nonradiative and radiative decay rates, luminescence decay time, intrinsic quantum efficiency, and Judd-Ofelt intensity parameter were determined. The monocentric luminescence and Judd-Ofelt parameters reveal the absence of symmetry around the europium center. CIE chromaticity coordinates, correlated color temperature values, color purity, and asymmetric ratios authenticate the color coordinates of the complexes in red region. Optical band gap values lie within the range of wide band gap semiconductors, indicating their utilization in military radars and biological labeling.