Effects of synergetic ligands on the thermal and radiative properties of Eu(TTA)3nL-doped poly(methyl methacrylate)

Rare earth complexes Eu(TTA)3nL (where TTA = α-thenoyltrifluoroacetonato, L = triophenylphosphine oxide, trioctylphosphine oxide, 1,10-phenanthroline, 2,2-bipy) were synthesized and doped in poly(methyl methacryate). Their thermal properties were studied by thermogravimetric analysis and differential scanning calorimetry. Among four rare earth complex-doped PMMAs with different synergetic ligands, Eu(TTA)3Dipy-doped PMMA shows the best thermal stability. Their optical properties were studied by means of fluorescence and fluorescence decay spectra. Furthermore, their Judd-Ofelt parameters Ω2, Ω4, and R have been computed from the fluorescence emission spectra and analyzed. The radiative properties, such as transition probabilities, emission cross-section, fluorescence branching ratios, and radiative lifetime were also discussed. The results reveal that the changing of synergetic ligands does not significantly influence the radiative lifetime of Eu3+ and the microenvironment around Eu3+ ions.