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Photoluminescent layered Y/Er silicates

Kostova, Mariya H.; Ananias, Duarte; Carlos, Luís D.; Rocha, João

The synthesis of new layered rare-earth silicates K3[Y1-aEraSi3O8(OH)2] (AV-22 materials) has been reported. The photoluminescence properties of Y/Er-AV-22 and the material resulting from its thermal degradation, K3[Y1-aEraSi3O9] (Y/Er-AV-23), have been studied and compared. Both materials have a similar chemical makeup and structures sharing analogous building blocks, hence providing a unique opportunity for r...

Data: 2008 | Origem: Estudo Geral - Universidade de Coimbra

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Photoluminescent Layered Lanthanide Silicate Nanoparticles

Ananias, Duarte; Ferdov, Stanislav; Paz, Filipe A. Almeida; Ferreira, Rute A. Sá; Ferreira, Artur; Geraldes, Carlos F. G. C.; Carlos, Luís D.; Lin, Zhi

The first examples of nanoparticles of pure layered Ln2(SiO4H)(OH)2(H2O)Cl (where Ln ) Eu, Gd, and Tb) and mixed microcrystalline layered lanthanide silicates containing different Eu/Gd and Tb/Gd ratios have been reported. The crystal structure of these silicates has been solved from synchrotron powder X-ray diffraction data. These materials display interesting and tuneable photoluminescence (PL) properties, su...

Data: 2008 | Origem: Estudo Geral - Universidade de Coimbra

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Energy Transfer and Emission Decay Kinetics in Mixed Microporous Lanthanide Sil...

Evans, Rachel C.; Ananias, Duarte; Douglas, Alastair; Douglas, Peter; Carlos, Luis D.; Rocha, João

We have investigated the energy transfer dynamics in mixed lanthanide open-framework silicates, known as Ln-AV-20 materials, with the stoichiometric formula Na1.08K0.5Ln1.14Si3O8.5·1.78H2O (Ln = Gd3+, Tb3+, Eu3+), using steady-state and time-resolved luminescence spectroscopy. Energy transfer between donor and acceptor Ln3+ ions is extremely efficient, even at low molar ratios of the acceptor Ln3+ (<5%). The pr...

Data: 2008 | Origem: Estudo Geral - Universidade de Coimbra

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Evolution of Photoluminescence across Dimensionality in Lanthanide Silicates

Kostova, Mariya H.; Ananias, Duarte; Paz, Filipe A. Almeida; Ferreira, Artur; Rocha, João; Carlos, Luís D.

The dehydratation process of layered lanthanide silicates K3[LnSi3O8(OH)2], Ln = Y, Eu, Tb, and Er, and the structural characterization of the obtained small-pore framework K3LnSi3O9, Ln = Y, Eu, Tb, and Er solids, named AV-23, have been reported. The structure of AV-23 has been solved by single-crystal X-ray diffraction (XRD) methods and further characterized by chemical analysis, thermogravimetry, scanning el...

Data: 2007 | Origem: Estudo Geral - Universidade de Coimbra

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