Luminescence features of mononuclear Sm(III) complexes with heterocyclic ligands

Abstract

Three ternary luminescent Sm(III) complexes were synthesized using 4-oxo-4H-1-benzopyran-3-carboxaldehyde (L), 4-Methyl-1,10-Phenanthroline (mphen), 2,2′-Biquinoline (biq), and Bathocuproine (bathocup) organic ligands. The synthesized materials were thoroughly characterized by ESI-MS+, CHN elemental analysis, Thermogravimetric analysis, UV–vis spectroscopy, FTIR, PXRD, FESEM, and PL spectroscopy techniques. The existence of sharp-narrow peaks in X-ray diffractogram confirmed crystallinity in the complexes. The ESI-MS+ and CHN data were in accordance with the proposed molecular formula of prepared materials. The optical bandgap (Eg) assessed from the Tauc plots suggested the direct electronic transition and semi-conducting character of the complexes with bandgap falling in the range 2.86–2.93 eV. The room temperature luminescence studies, carried out in the solution and powder state displayed three noticeable peaks from excited (4G5/2) to ground state (6H5/2, 7/2, 9/2) at ∼566, 601, and 647 nm, under UV excitation. The orange-red emission by the complexes was also confirmed through CIE chromaticity. The complexes possess good thermal stability. The prepared complexes might be potential candidate for liquid lasers, bio-assays, and solid-state lighting applications.