Electrospinning Preparation and Photoluminescence Properties of Rare-Earth Complex/Polymer Composite Fibers

Composite fibers of poly(vinyl pyrrolidone) (PVP, M w ≈ 1 300 000) and europium complex Eu(BA) 3 (TPPO) 2 (BA =1-benzoylacetone; TPPO = triphenylphosphine oxide) with strong photoluminescence were prepared by electrospinning. Their luminescent properties were studied in comparison to that of the pure complex. The results indicate that due to decreased symmetry in the composites the excitation bands are split into two different components, peaking at ∼246 and ∼336 nm, respectively, while the ratio of the electronic dipole 5 D 0 - 7 F 2 transitions to the magnetic dipole 5 D 0 - 7 F 1 ones in the emission spectra becomes a little larger. The room temperature fluorescence lifetime for the 5 D 0 level becomes shorter due to increased radiative and nonradiative transition rates. The temperature dependence of photoluminescence was investigated under 325-nm excitation. It is interesting to observe that in the composite fiber the total emission intensity of the Eu 3+ ions changes little below 150 K, while in the pure complex the intensity decreases monotonically with increasing temperature. In addition, the composite fibers exhibit better photostability exposed to ultraviolet lights. These novel luminescent composite fibers have potential application in nanodevices.