Preparation, characterization, and spectroscopic properties of PC/PMMA doped blends: study of the effect of rare-earth doping on luminescence, quenching rate, and lifetime enhancement.
Optical properties of highly transparent blends formed by bisphenol A polycarbonate (PC) and poly(methyl methacrylate) (PMMA) and doped with either europium(III) thenoyltrifluoroacetone hydrate [Eu(TTA)(3)-hydrate] or terbium(III) acetylacetonate hydrate [Tb(ACAC)(3)-hydrate] were studied. From the absorption/emission spectra (200 to 800 nm), percolation limits of less than 0.4 wt/wt% for Eu and above 0.7 wt/wt% for Tb were found. Lifetimes for 20/80 and 60/40 Tb-doped blends were from 1.0 to 1.5 ms, respectively, about 5 times longer than for a similar blend prepared with Langmuir-Blodgett film. For blends doped with Eu, the lifetimes were from 0.4 to 0.8 ms, almost double that for the pure complex. The results indicated interactions between the PC/PMMA blends and the rare-earth ion complex. Particularly, photoluminescent spectra evidenced the incorporation of the Eu(3+) and Tb(3+) ions into the blend, with quenching observed near 1.0 wt/wt%, except for the 20/80 blend doped with Eu ion, in which luminescence increased to 5 wt/wt %.
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Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020-900, Maringá, Paraná, Brazil.
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