LAUSR

Six luminescent, bright red Eu(III) complexes with a β-keto-carboxylic acid as prime ligand and N-donor aromatic systems as auxillary ligand were synthesised via ecologically efficient grinding method. The distinctive red peak (5D0 → 7F2) of Eu(III) ion is exhibited in emission spectra of all complexes. The luminescent properties of complexes were analysed through decay time, color coordinates, luminescence efficiency and Judd Ofelt parameters. The value of Ω2 is found to be higher than Ω4 which indicated hypersensitive nature of 5D0 → 7F2 transition. The results established the complexes as a strong contender for red light emitting display devices. The fluorescence branching ratios, stimulated emission cross section, gain band width and optical gain showed the good lasing strength of 5D0 → 7F2 transition of complexes. The complexes exhibited decent thermal stability and have optical energy band gap value in semiconductor range, thus can have relevance in optoelectronic devices. Energy transfer mechanism was investigated for complexes which affirmed the efficacious transfer of energy from ligands to Eu(III) ion. The synthesised complexes were also assayed for antimicrobial and antioxidant properties. All complexes are reported to show better antioxidant behaviour than the prime ligand and also exhibited upstanding antibacterial activities.