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

The binary europium complex EuL3 （L=4-tert-butylbenzoate） and ternary europium complexes EuL3TTAo.I （TTA=2- thenoyltrifluoroacetone）, EuL3DBMo.5 （DBM=dibenzoylmethane） and EuL3pheno.5 （phen=l, 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〈EuL3pheno.5/PMMA〈EuL3DBMo.5/ PMMA〈EuL3TTAo.I/PMMA. It indicated that the introduction of a small amount of I^-diketone ligand affected the optimum excita- tion 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 lumi- nescence intensity of the polymer composites.

Optical properties and Judd-Ofelt analysis of Nd2O3 nanocrystals embedded in polymethyl methacrylate

PMMA matrices were doped with nano-crystalline neodymium oxides synthesized by thermal decomposition process. X-ray diffraction and high-resolution transmission electron microscopy measurements were carried out to investigate the structure, phase, and the morphology of the Nd_2O_3 nanocrystals and those embedded in the PMMA matrix. The average grain sizes were estimated 35 ± 6 nm and 46 ± 4 nm for non-annealed and annealed Nd_2O_3 particles, respectively. The grain size distributions（GSD） were calculated from the diffraction peaks of the annealed and non-annealed Nd_2O_3 powders and doped PMMA samples. The mass density, refractive index. UV-Visible absorption spectra were measured and the data were analyzed using the Judd-Ofelt approach to determine the oscillator strengths, the spontaneous emission probabilities and the branching ratios as a function of the nano-crystalline Nd_2O_3 content in the range of 0.1 wt.%-20 wt.% of MMA. Luminescence spectra upon 808 nm diode laser excitation were carried out in the wavelength range of 850-1550 nm at room temperature. The photoluminescence study has shown that the reasonably sharp emission peaks were observed upon heat treatment at 800 ℃ for 24 h for all concentrations of Nd_2O_3 nanopowders in PMMA. The infrared laser transition of Nd^（3＋） ions at about 1.06 μm due to the ~4F_（3/2）→~4I_（11/2） transition was analyzed and discussed in Nd_2O_3 system for their possible applications in the photonic technology.