Synthesis and photo-physics of red emitting europium complexes: An estimation of the role of ancillary ligand by chemical partition of radiative decay rate

Rashid Ilmi, Ashanul Haque, Muhammad Khan

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Three highly luminescent Eu(III) complexes of the type [Eu(β-diket.)3(tm-phen)] where β-diket. = hexafluoroacetylacetone (hfaa), btfa; 4,4,4-trifluoro-1-phenyl-1,3-butanedione (btfa), 2-thenoyltrifluoroacetone (tta) and tm-phen = 3,4,7,8-tetramethyl-1,10-phenanthroline have been synthesized and characterized. The detailed photophysical properties of the complexes were analyzed both theoretically and experimentally. The theoretical photophysical properties calculated using the LUMPAC program [1] are in excellent agreement with experimental results. The Judd-Ofelt (J-O) parameters (Ω2 and Ω4), radiative (Arad) and non-radiative (Anrad) decay rates were calculated and discussed. Chemical partition of the radiative decay rates (Arad) of electric-dipole transitions revealed that β-diketone contributes 77 to 84% while tm-phen contributes 22 to 16% towards the Arad. The intramolecular energy transfer (WET) and back-energy transfer (WBT) rate are predicted from the singlet (S1) and triplet (T1) levels to the emissive 5D1 and 5D0 states for Eu(III) and follow the path S0 → S1 → T15D15D07F0,4. The complexes emit typical Eu(III) red emission with long luminescence lifetime (0.75–0.88 ms), show high intrinsic quantum yield (ϕLn) (66–70%) and may be used as one of the red components in light emitting devices.

Original languageEnglish
Pages (from-to)135-144
Number of pages10
JournalJournal of Photochemistry and Photobiology A: Chemistry
Publication statusPublished - Feb 1 2019



  • Fluorinated β-diketone
  • Radiative and non-radiative decay rates
  • Sparkle/RM1

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Physics and Astronomy(all)

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