Luminescent Hybrid Materials Research Articles

Construction of lanthanide luminescent molecular-based hybrid material using modified functional bridge chemical bonded with silica

The study focuses on the syntheses of modified chloronictinic acid by (3-aminopropyl)triethoxysilane and the preparation of their corresponding organic–inorganic molecular-based hybrid material with the two components equipped with covalent bonds. The bridging unit is a derivative of 2-chloronictinic acid (ClNIC-Si) which is utilized to coordinate to Tb 3+ or Eu 3+ (abbreviated as RE 3+) and further introduced into silica matrices by Si O bonds after hydrolysis and polycondensation processes. Ultraviolet absorption, phosphorescence spectra, and fluorescence spectra were applied to characterize the photophysical properties of the obtained hybrid material and the above spectroscopic data present that the triplet energy of modified chloronictinic acid efficiently initiates the antenna effect and matches with the emissive energy level of RE 3+. Accordingly, the intramolecular energy transfer process completed within these molecular-based hybrids and strong green or red emissions of RE 3+ have been obtained.

A Novel Way to Luminescent Ter-bium Molecular-Scale Hybrid Materials: Modified Heterocyclic Ligands Covalently Bonded with Silica

The syntheses of modified nicotinic and picolinic acid by (3-aminopropyl)triethoxysilane and the preparation of their corresponding organic−inorganic molecular-based hybrid materials with the two components equipped with covalent bonds are described. The organic part is a derivative of heterocyclic compounds which is used to coordinate to Tb3+ and further introduced into silica matrixes by Si−O bonds after hydrolysis and polycondensation processes. According to the Judd-Ofelt theory, covalency increases with the increasing reciprocal energy difference between the 4fN and 4fN-15d1 configurations. Infrared, ultraviolet absorption, phosphorescence spectra, and luminescence spectra were applied to characterize the photophysical properties of the obtained hybrid material, and the above spectroscopic data revealed that the triplet energy of modified heterocyclic acid especially the modified nicotinic acid matched the emissive energy level of Tb3+. In this way, an intramolecular energy transfer process took plac...

Near-Infrared Luminescent Hybrid Materials Doped with Lanthanide (Ln) Complexes (Ln = Nd, Yb) and Their Possible Laser Application

The crystal structures of ternary Ln(DBM)(3)phen complexes (DBM = dibenzoylmethane, phen = 1,10-phenanthroline, and Ln = Nd, Yb) and their in situ syntheses via the sol-gel process are reported. The properties of the Ln(DBM)(3)phen complexes and their corresponding Ln(3+)/DBM/phen-co-doped luminescent hybrid gels obtained via an in situ method (Ln-D-P gel) have been studied. The results reveal that the lanthanide complexes are successfully in situ synthesized in the corresponding Ln-D-P gels. Both Ln(DBM)(3)phen complexes and Ln-D-P gels display sensitized near-infrared (NIR) luminescence upon excitation at the maximum absorption of the ligands, which contributes to the efficient energy transfer from the ligands to the Ln(3+) ions (Ln = Nd, Yb), an antenna effect. The radiative properties of the Nd(3+) ion in a Nd-D-P gel are discussed using Judd-Ofelt analysis, which indicates that the (4)F(3/2) --> (4)I(11/2) transition of the Nd(3+) ion in the Nd-D-P gel can be considered as a possible laser transition.

An unusual way to luminescent terbium molecular-level hybrid materials: Modified methyl benzoic acid covalently bonded with silica as a bridge

The syntheses of modified ortho or meta methylbenzoic acid by (3-aminopropyl)triethoxysilane and the preparation of their corresponding organic–inorganic molecular-based hybrid material with the two components equipped with covalent bonds are described. The organic part is a derivative of methyl benzoic acid, which is used to coordinate to Tb3+ and further introduced into silica matrices by Si–O bonds after hydrolysis and polycondensation processes. The Judd–Ofelt theory proves that covalency increases along with increasing reciprocal energy difference between the 4fN and 4fN−15d1 configurations. Ultraviolet absorption, phosphorescence spectra, and luminescence spectra were applied to characterize the photophysical properties of the obtained hybrid material, and the above spectroscopic data reveal that the triplet energy of modified methyl benzoic acid matches with the emissive energy level of Tb3+. In this way, the intramolecular energy transfer process took place within these molecular-based hybrids, and strong green emission of Tb3+ was obtained.

A Novel Way to Prepare Luminescent Terbium Molecular-Scale Hybrid Materials: Modified Heterocyclic Ligands Covalently Bonded with Silica

The syntheses of modified nicotinic and picolinic acid by (3-aminopropyl)triethoxysilane and the preparation of their corresponding organic−inorganic molecular-based hybrid materials with the two components equipped with covalent bonds are described. The organic part is a derivative of heterocyclic compounds which is used to coordinate to Tb3+ and further introduced into silica matrixes by Si−O bonds after hydrolysis and polycondensation processes. According to the Judd-Ofelt theory, covalency increases with the increasing reciprocal energy difference between the 4fN and 4fN-15d1 configurations. Infrared, ultraviolet absorption, phosphorescence spectra, and luminescence spectra were applied to characterize the photophysical properties of the obtained hybrid material, and the above spectroscopic data revealed that the triplet energy of modified heterocyclic acid especially the modified nicotinic acid matched the emissive energy level of Tb3+. In this way, an intramolecular energy transfer process took place within these molecular-based hybrids and strong green emission of Tb3+ was achieved.

Energy transfer in luminescent Tb- and Eu-containing layered double hydroxides

The synthesis of new Tb- and Eu-containing LDH-based luminescent hybrid materials with quantum yields up to 45% is described; energy transfer studies in corresponding mixed Tb3+/Eu3+ systems revealed highly efficient ligand→Tb3+/Eu3+ and Tb3+→Eu3+ communication channels.

Molecular design of luminescent organic-inorganic hybrid materials activated by europium (III) ions

Abstract Luminescent hybrid materials consisting in rare-earth (Eu 3+ , Gd 3+ ) organic complexes covalently attached to a silica-based network have been obtained by a sol–gel process. Four dicarboxylic acids with different aromatic subunits (dipicolinic acid, 4-phenyl-2,6-pyridinedicarboxylic acid, 4-(phenylethynyl)-2,6-pyridinedicarboxylic acid and 2,6-Bis(3-carboxy-1-pyrazolyl)pyridine) have been chosen as ligands for Ln 3+ ions. They were grafted to 3-aminopropyltriethoxysilane (APTES) to give organically modified alkoxysilanes that were used as molecular precursors for the preparation of hybrid materials. Ln 3+ first coordination sphere, composition of the siloxane matrix and connection between the organic and inorganic parts have been characterized by infrared spectroscopy, by 13 C 29 Si solid-state NMR as well as by elemental analyses. UV excitation in the organic component resulted in strong emission from Eu 3+ ions due to an efficient ligand-to-metal energy transfer. As compared to reference organic molecules, hybrid samples exhibited similar emission properties under UV excitation in addition to mainly unchanged excited states lifetimes. However, by direct excitation of the Eu 3+ - 5 D 0 energy level, the presence of two different site distributions were evidenced in the four hybrid compounds. Emission features related to each of these site distributions and their respective attribution were investigated. Variations in the relative emission intensities were observed according to the nature of the organic chromophore. These variations were discussed in relation to the ATE (Absorption-Transfer-Emission) mechanism and to the relative energy positions of the ligand and the rare-earth ions respectively.

Luminescent inorganic networks

AbstractSilica‐based inorganic networks combined with organic rare earth complexes should lead to a new class of luminescent materials, adding the chemical stability of silica to the strong UV absorption of organic ligands and the emissive properties of rare earth ions. This concept is demonstrated by the preparation of silica xerogels containing benzoic acid in its network and subsequent reaction (ion exchange) of these gels with terbium chloride solution. The product yields green luminescence similar to the one of solid terbium benzoate. Alternatively, complete rare earth complexes (example: europium thenoyltrifluoracetonate) may be immobilized in silica xerogels, yielding luminescent hybrid materials.