Judd-Ofelt analysis of some novel Eu3+ complexes featuring Kojic acid and N, N’- donor ligands

Abstract

Three ternary complexes featuring Eu3+ have been prepared by using primary ligand Kojic acid and secondary ligands 4-methyl-110-phenanthroline; 3,4,7,8-tetramethyl-110-phenanthroline and bathocuproine. Characterization of synthesized complexes was carried out using spectroscopic techniques: FTIR, elemental analysis, ESI-MS+, UV, TGA, FESEM, P-XRD, and Photoluminescence studies (PL). Results of P-XRD revealed that the complexes possess crystalline nature. Four specific emission peaks of Eu3+ have been noticed, corresponding to 5D0 → 7FJ transitions, where J = 0–3 at about 580, 595, 614, and 650 nm, respectively. The Judd-Ofelt intensity parameters, radiative lifetime, quantum efficiency, branching ratio, and stimulated emission of complexes were determined. The CIE color coordinates revealed monochromatic red emission by the complexes with high color purity. The higher values of stimulated emission cross-sections and branching ratios of the complexes show that these complexes might be potentially applicable in laser systems. The CCT values below 5000 K suggest warm light emission by the complexes. The prepared ternary Eu3+ complexes have higher thermal stability of about 250 °C. Based on the result obtained from the above studies, these complexes could be a promising candidate for laser systems, optical applications, OLEDs, display devices, photophysical, and biomedical science.