Preparation and optical investigation of green luminescent ternary terbium complexes with aromatic β-diketone

Abstract

Green luminescent complexes of terbium based on derivatives of 1,10-phenanthroline auxiliary ligand and 1-phenyl-1,3-butanedione (PBD) with general formula [Tb(PBD)3L] were synthesized. The complexes were characterized by spectroscopic and thermal methods. Photoluminescence spectra demonstrated that on excitation under UV radiations, four emission peaks were displayed in the emission spectra. These characteristic peaks appeared due to transition from the energized (5D4) to the ground state (7FJ) positioned at 491, 547, 584, 622 nm, where J = 6–3 respectively. The hypersensitive peak located at 547 nm is responsible for the characteristic green emission of terbium ion. Absorption and electrochemical analytical results point out the application of synthesized complexes in lighting and displays. Optical and electronic band gap in 3–4 eV range were also found comparable to each other and revealed the use of ternary terbium complexes as semiconductor material.