Time, space, and spectrally resolved studies on J-aggregate interactions in zeolite L nanochannels
ABSTRACT Temporally and spectrally resolved confocal microscopy has been used to explore the behavior of pyronine intercalated zeolite L crystals at different loadings. The low pyronine loading of 0.6% exhibits photophysical behavior similar to that of the free molecule in solution, indicating molecules are isolated from each other in the crystal channels. The higher loading of 20% results in a dye gradient along the channel axis, and the presence of an additional red-shifted spectroscopic transition, with shorter lifetimes. The new band is assigned to an inline arrangement of the molecules undergoing a J-aggregate-type coupling, a process so far not observed in subnanometer channels.
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ABSTRACT: Different laser dyes (with special interest in boron dipyrromethene) are incorporated as guests into the channels of zeolite L. The resulting doped material is fully characterized by steady-state and time-resolved photophysical techniques. The pores of zeolite L are filled with high amounts of dyes, which are exclusively present in their monomeric form and aligned in a preferential orientation, thus generating an organized photoactive material. The ordered disposition of the dye, mostly along the direction of the zeolite L nanochannels, was confirmed by confocal fluorescence microscopy. A careful selection of fluorophores along with controlled loading allows the harvest of light from the entire ultraviolet/visible region for conversion into white light, or alternatively, tuning of the emission in the blue, green, and red regions, owing to the presence of energy-transfer processes in the antenna systems built up in this work.ChemPlusChem 01/2012; 77(1). DOI:10.1002/cplu.201100020 · 3.24 Impact Factor
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ABSTRACT: A tough challenge in nanomaterials chemistry is the determination of the structure of multicomponent nanosystems. Dye−zeolite L composites are building blocks of hierarchically organized multifunctional materials for technological applications. Supramolecular organization inside zeolite L nanochannels, which governs electronic properties, is barely understood. This is especially true for confined close-packed dye molecules, a regime not investigated in applications yet and that might have great potential for future development in this field. Here we realize for the first time composites of zeolite L with maximally packed fluorenone molecules and elucidate their structure by integrated multitechnique analyses. By IR spectroscopy, thermogravimetric analysis, and X-ray diffraction, we establish the maximum degree of dye loading obtained (1.5 molecules per unit cell), and by modeling we reveal that at these conditions fluorenone molecules form quasi 1-D supramolecular nanoladders running along the zeolite channels. Spatial and morphological control provided by the nanoporous matrix combined with a complex blend of strong dye−zeolite and weaker dye−dye van der Waals interactions lie at the origin of this unique architecture, which is also stabilized by the hydrogen bond network of coadsorbed water molecules surrounding the dye nanoladder and penetrating between its rungs.The Journal of Physical Chemistry C 07/2014; 118(29):15732-15743. DOI:10.1021/jp505600e · 4.84 Impact Factor
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ABSTRACT: Some multi-component hybrids based zeolite L/A are prepared. Firstly zeolite A/L are loaded with lanthanide complexes (Eu-DBM or Tb-AA (acetylacetone = AA, dibenzoylmethane = DBM)) into their channels. Secondly, 3-methacryloyloxypropyltrimethoxysilane (γ-MPS) is used to covalently graft onto the surface of functionalized zeolite A/L (Si-[ZA/LEu-DBM(Tb-AA)]). Thirdly, lanthanide ions (Eu3+/Tb3+) are coordinated to the functionalized zeolite A/L and ligands (phen (1,10-phenanthroline) or bipy (2,2’-bipyridyl)) are introduced by a ship-in-bottle method. The inner-outside double modifications of ZA/L with lanthanide complexes achieve the final hybrids and are characterized by means of XRD, FT-IR, UV-vis DRS, SEM and luminescence spectroscopy, some of which display white or near-white light emission. Furtherly, selected above hybrids are fabricated into PEMA/PMMA (poly ethyl methylacryate/poly methyl methacrylate) host to prepare luminescent polymer films. These results provide abundant data to be expected to have potential application in various practical ﬁelds.Photochemical and Photobiological Sciences 11/2014; 14(2). DOI:10.1039/C4PP00364K · 2.94 Impact Factor