Luminescent properties of europium ions in CaAl₂SiO₆

The CaAl₂SiO₆ aluminosilicate nanocrystals doped with europium(II) and europium(III) ions have been synthesized using the sol–gel method. To obtain Eu²⁺ ions, samples were annealed in the reducing atmosphere. The XRD diffractograms, excitation and emission spectra, as well as the decay time profiles were measured and analyzed. Nanocrystals doped with Eu³⁺ ions possess sharp emission peaks, which are assigned to the ⁵D₀ → ⁷F_J transitions, where the most intensive is ⁵D₀ → ⁷F₂ luminescence. The decay curve of the europium(III) emission is single exponential. The asymmetry factor around the Eu³⁺ ions was calculated from the emission spectrum. CaAl₂SiO₆ nanocrystallites containing Eu²⁺ ions possess the broad emission band in the visible range with maximum at 530 nm. Emission decay time of the 0.2% sample is equal 1.7 μs at 300 K and has multi exponential character. - Highlights: • The CaAl₂SiO₆ nanocrystals doped with Eu were synthesized with the sol–gel method. • The CaAl₂SiO₆:Eu²⁺ nanocrystals possess the broad emission in the visible region. • Nanocrystals doped with Eu³⁺ ions have the sharp emission from the ⁵D₀ level.