Luminescence properties of polymers containing europium complexes with 4-tert-butylbenzoic acid

Abstract

The binary europium complex EuL3 (L=4-tert-butylbenzoate) and ternary europium complexes EuL3TTA0.1 (TTA=2- thenoyltrifluoroacetone), EuL3DBM0.5 (DBM=dibenzoylmethane) and EuL3phen0.5 (phen=1, 10-phenanthroline) were synthesized. The poly(methyl methacrylate) (PMMA) or copolymer of methyl methacrylate (MMA) with acrylic acid (AA) composites doped with europium complexes were prepared by radical in-situ polymerization. The influences of the europium complexes, ligands, N,N-dimethylformamide (DMF) and monomers on the luminescence properties of the doped polymers were investigated. The results showed that the fluorescence excitation bands of binary and ternary complexes were in accordance with their ultraviolet absorption bands. All the complexes and the doped polymer composites exhibited the ligand-sensitized red characteristic emission of Eu3+ ion. The fluorescence intensity of the polymer composites increased in the sequence of EuL3/PMMA<EuL3phen0.5/PMMA<EuL3DBM0.5/ PMMA<EuL3TTA0.1/PMMA. It indicated that the introduction of a small amount of β-diketone ligand affected the optimum excitation wavelength and the fluorescence intensity of polymer composites. Furthermore, DMF remarkably increased the luminescence intensity and transparence of the doped polymer composites. However, introduction of acrylic acid comonomer decreased the luminescence intensity of the polymer composites.