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

Abstract

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 ⁴F_9/2 → ⁶H_13/2 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.