Multi-color fluorescence in rare earth acetylacetonate hydrate doped poly methyl methacrylate

Europium and terbium acetylacetonate hydrates were doped into poly methyl methacrylate (PMMA). Efficient purplish-red and green fluorescence was obtained from europium acetylacetonate hydrates (EAH) and terbium acetylacetonate hydrates (TAH) doped PMMA respectively. Judd-Ofelt parameters Ω₂ (19.73×10^-20 cm²) and Ω₄ (2.19×10^-20 cm²) indicate a high inversion asymmetric and strong covalent environment in PMMA. The maximum stimulated emission cross-sections for the ⁵D₀→ ⁷F_J (J=1, 2 and 4) transitions in EAH doped PMMA were calculated to be 0.38×10^-21, 4.90×10^-21 and 0.36×10^-21 cm², respectively. Variable fluorescence color can be efficiently achieved from the cooperation of three fluorescence colors offered by red (Eu³⁺), green (Tb³⁺) and blue (ligand) in EAH/TAH codoped PMMA by adjusting the excitation wavelength. These results indicate that PMMA is an effective photoluminescence co-sensitizer and PMMA doped with rare earth acetylacetonate hydrates is a promising candidate for a series of optoelectronic functional devices.