Highly luminescent polycaprolactone films doped with diaquatris(thenoyltrifluoroacetonate)europium(III) complex

In this work we report the preparation, characterization, thermal and luminescence properties of highly luminescent polycaprolactone (PCL) polymer films incorporated with diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(tta)3(H2O)2] (doping concentration at 1, 2, 5, 10 and 15 wt%). Thermogravimetry analysis (TGA) showed no weight loss in the range of 323-473 K for the polymeric systems, suggesting that the interaction between the polymer matrix and the Eu3+-complex occurs when the carbonyl groups along the polymer backbone substitute the water molecules in the complex precursor. Differential scanning calorimetry (DSC) showed no significant changes in Tm for the film samples, however crystallinity is affected by non combined complex in the polymer chains. The changes in the curve-fitted FTIR spectral areas for each component peak are gradually changed with the increase of doping concentration. The displacement of the C-O for the β-diketonate complex to new positions in PCLE systems provide good evidence that the metal ion is coordinated through the oxygen atoms deriving from PCL. The observation of characteristic emission bands arising from the 5D0→7FJ transitions (J=0-4) dominated by the hypersensitive 5D0→7F2 transition at around 614 nm of Eu3+ ion indicates the incorporation of the Eu3+ ions in the system corroborating with the CHN and IR data. Luminescence quenching is observed, with the film of 5% doping concentration of the Eu3+ complexes showing the highest luminescence intensity among all samples.