Optimizing white light emission in Dy(iii) complexes: impact of energy transfer from mono and bidentate ligands on luminescence.

Complexes of dysprosium(iii) ions with 1,1,1,5,5,5-hexafluoro-2,4-pentanedione featuring various mono and bi-dentate neutral ligands have been prepared and thoroughly investigated. The synthesized complexes exhibit an octa-coordinated environment, achieved by stoichiometrically combining organic ligands and Dy(iii) ions. This octa-coordination environment of Dy(iii) ion was confirmed by FT-IR spectroscopy, thermogravimetry and elemental analysis. Near-white light (NWL) is emitted when complexes were exposed to UV radiation, indicating a significant flow of energy from the sensitizing moieties towards the Dy(iii) ion. This NWL emission might have resulted due to a balance between the intensities corresponding to emission peaks at 480 nm (blue) and 575 nm (yellow) in Dy1-Dy3. Emission spectra recorded at different excitation wavelength were utilized to study the tunability of CIE color coordinates. In addition to their high thermal stability, the complexes display bipolar paramagnetic shifts in their NMR spectra. The 4F9/2 → 6H13/2 transition, contributing ∼62% of the total emission, stands out as a promising candidate for laser amplification due to its dominance in the emission spectra. Additionally, NWL emission observed in a solid Dy(iii) complex opens intriguing possibilities for its application in next-generation white-light emitting devices.

Computational and optoelectronic investigations of red-emissive europium (III) ß-diketonate with n-donor ligands for display applications.

Europium complexes exhibiting red luminescence were prepared by employing ß-diketone as main ligand and 1,10-phenanthroline as an additional ligand. Various methods, including 1H NMR, IR spectroscopy and analysis of optical band gap were employed to examine these complexes. The luminescent photophysical properties were investigated using PL spectroscopy and theoretical calculations were conducted to explore radiative transitions probabilities and Judd-Ofelt (J-O) parameters for transitions of type 5D0 → 7F2, 4. J-O parameters were determined using the JOES computer program and results were in good agreement with the outcomes obtained experimentally. The luminescence analysis results have verified the vibrant, single-color red emission of the prepared complexes. The band gap of ternary europium complexes, determined optically, electronically, and theoretically, falls within the range of 3-4 eV. This similarity indicates that these complexes are potentially suitable as semiconductor materials. The results from absorption, electrochemical and photophysical analyses indicate the potential use of synthesized complexes in lighting and display applications.