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The spectroscopic behavior of ionic Eu3+ or Tb3+ complexes of an aromatic carboxyl-functionalized organic salt as well as those of the hybrid materials derived from adsorption of the ionic complexes on Laponite clay are reported. X-ray diffraction (XRD) patterns suggest that the complexes are mainly adsorbed on the outer surfaces of the Laponite disks rather than intercalated within the interlayer spaces. Photophysical data showed that the energy-transfer efficiency from the ligand to Eu3+ ions in the hybrid material is increased remarkably with respect to the corresponding ionic complex. The hybrid material containing the Eu3+ complex shows bright red emission from the prominent 5D0→7F2 transition of Eu3+ ions, and that containing the Tb3+ complex exhibits bright green emission due to the dominant 5D4→7F5 transition of Tb3+ ions. [ABSTRACT FROM AUTHOR]

The acidity of europium(III)-exchanged zeolite L (Eu3+/ZL) and its influence on the luminescence performances of encapsulated europium(III) β-diketonate complexes are reported. The results indicate the importance of understanding the acidity of Eu3+/ZL in the preparation of luminescent host-guest materials of zeolite L crystals and europium(III) β-diketonate complexes. The acidity of Eu3+/ZL was determined roughly by using a dye (thionine) as the probe molecule. The luminescence performances of the host-guest materials, including excitation and emission spectra, lifetime of Eu3+ ions, quantum yield, and energy transfer efficiency, have been investigated. The luminescence behavior of the host-guest materials can be tuned by changing the acidity inside the channels of the zeolite L crystals and can potentially be used as a sensor for detecting ammonia. [ABSTRACT FROM AUTHOR]

Herein, we report a facile method to prepare thermally reversible, flexible, transparent, and luminescent ionic organosilica gels with tunable emission colors. The reaction of an amino-functionalized ionic liquid ([NH2-Bim]Br) with 3-(triethoxysilyl)propyl isocyanate results in an ionic-liquid-modified alkoxysilane, the hydrolysis and condensation of which lead to thermally reversible, flexible, and luminescent ionic gels in the presence of lanthanide species. The luminescence color can be fine-tuned by changing the Ln3+ ions (Eu3+, Tb3+, or a mixture of Eu3+ and Tb3+) and by changing the excitation wavelength. The absolute quantum yields of the flexible luminescent gels with europium(III) and terbium(III) complexes are determined to be 15 and 21 %, respectively, by using an integrating sphere. The thermal reversibility of the organosilicas makes them attractive for the development of flexible optical devices and flexible luminescent devices such as organic light-emitting diodes (OLEDs). [ABSTRACT FROM AUTHOR]