FTIR spectroscopic analysis and STM studies of electroluminescent Eu(DBM)3 bath thin films vacuum deposited onto Au surface

White Light Emissive Eu(III) Complexes through Ligand Engineering and their Applications in Cool Near Ultraviolet White Light Emitting Diodes and Thermometer

In pursuit of enhancing white light quality for solid-state lighting (SSL) applications, an attempt has been made to design novel imidazo-bipyridyl ligands as an ancillary ligand to obtain multiple emissions (mimic sunlight) in the Eu-complex. By strategically modifying the phenanthroline core with imidazo-bipyridyl incorporation with 1 or 2-Napthyl groups at the C1 position, the excitation spectral line is successfully shifted from Ultraviolet (UV) to near UV/visible spectrum (where the LED emission occurs). The ligands showed greenish blue emission in solid and solution. Density Functional Theory (DFT) calculations were utilized to understand the energy transfer processes from ligand to Eu ion in the Eu complexes. The analysis revealed that the energy transfer is incomplete, primarily attributed to the proximity of triplet state energy levels to the resonance level of Eu(III) ions as reflected in solvatochromism. These complexes exhibit a unique dual emissive behavior (emitting multi-color) including white light across various solvents. These complexes hold great promise as single-component white light-emissive materials, with potential applications in white light-emitting diodes (WLED). The fabricated white LED showed an excellent color rendering index (CRI ~93 %). Beyond lighting, this distinctive property opens avenues for temperature sensing ([Eu(DBM)31-Naph] shows the highest sensitivity of Sr=10.97 %, and [Eu(DBM)32-Naph] shows the highest sensitivity of Sr=5.5 % at 333 K) and vapoluminescent (acid-base on-off-on luminescence) studies. This research pioneers the development of these complexes as potential single-component materials for superior white LEDs, underlining their multifaceted utility in cutting-edge lighting and sensing technologies.

Structure, luminescence and magnetic properties of an erbium(iii) β-diketonate homodinuclear complex

The photoluminescence properties and field-induced single-molecule-magnetic behavior of a novel erbium(iii) β-diketonate homodinuclear complex, [Er₂(nd)₆(μ-bpm)] (nd = 2,4-nonanedione and bpm = 2,2′-bipyrimidine), are presented.

Slow magnetic relaxation and photoluminescent properties of a highly coordinated erbium(iii) complex with dibenzoylmethane and 2,2′-bipyridine

The luminescence and magnetic properties of a bifunctional highly coordinated Er(iii) β-diketonate complex are presented, together with its synthesis and structure.

Theoretical study, and infrared and Raman spectra of copper(II) chelated complex with dibenzoylmethane

There are some discrepancies in both the vibrational assignments and in the metal-ligand (M-L) bond strengths predicted in the previous studies on the copper (II) chelated complex of dibenzoylmethane, Cu(dbm)2. Also, there is a lack of theoretical structure, Raman spectrum and full vibrational assignment for Cu(dbm)2 in the literatures. Density functional theory (DFT) at the B3LYP level and also MP2 calculations using different basis sets, besides Natural Bond Orbital (NBO) and Atoms-in-Molecules (AIM) analyses, have been employed to investigate the effect of methyl substitution with the phenyl group on the stabilities of bis(acetylacetonate) copper (II), Cu(acac)2, and Cu(dbm)2 complexes and the electron delocalization in their chelated rings. Measured solid phase infrared and Raman bands for Cu(dbm)2 complex have been interpreted in terms of the calculated vibrational modes and detailed assignment has been presented. We concluded that, theoretically, the results of charge transfer studies, and experimentally, in-phase symmetric O-Cu-O stretching mode of these complexes are very useful measures for M-L bond strength. The electron delocalization in the chelated rings and the M-L bond strength in Cu(dbm)2 are concluded to be higher than those in Cu(acac)2. The calculated geometries and vibrational results are in good agreement with the experimental data.