| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Parola, A. Jorge
Universidade Nova de Lisboa
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (7/7 displayed)
- 2023New organic platform to integrated photonic device fabrication
- 2020Unveiling the Colours of Cellulose Nitrate Black and White Film-based Negatives in Colonial Photographycitations
- 2020Energy Transfer between CNT Surface and −Re(CO)3(phen)+* Pendants Grafted to P4VP in Nanohybrid Shish-Kebob-like Structurescitations
- 2017Electronic and charge transfer properties of bio-inspired flavylium ions for applications in TiO2-based dye-sensitized solar cellscitations
- 2013Colouring glasses using nanoparticles synthesized within polyelectrolyte layer-by-layer filmscitations
- 2010Formation of Eu(III) Nanoparticles on Borosilicate Sol-Gel Studied with Time-Resolved Luminescence Techniquescitations
- 2001Metal-metal interaction in polynuclear complexes with cyanide bridges: Synthesis, characterisation, and theoretical studiescitations
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article
Formation of Eu(III) Nanoparticles on Borosilicate Sol-Gel Studied with Time-Resolved Luminescence Techniques
Abstract
The formation of Eu(III) nanoparticles in borosilicate sol-gels and the glass formation heat treatment effect on those particles were studied using luminescence techniques. The presence of the particles was observed using transmission electron microscopy (TEM) images followed by analysis with energy dispersive X-ray spectroscopy (EDS). These experiments showed the presence of particles with a large quantity of europium and chlorine and only small amounts of oxygen with sizes ranging from 30 to 100 nm. Heat treatment at 400, 600, and 800 degrees C lead to glass samples in which those particles were no longer observed. Steady-state and time-resolved luminescence techniques allowed a detailed study of Eu(III) photophysics in sot-gel and glass samples. In sol-gel matrices, the D-5(0) -> F-7(0) transition is very weak, hinting at Eu(III) species experiencing a rather symmetric crystal field. The D-5(0) -> F-7(2) transition intensity is not very strong, which according to a Judd-Ofelt analysis indicates low interaction with the anions present in the sol-gel matrices. This picture reverses after heat treatment, indicating a replacement of chloride anions with oxygen as preferential ligands of Eu(III). Time-resolved luminescence shows in a more detailed way these aspects. Sol-gel samples display nonexponential kinetics, which are attributed to Eu(III) species present in the nanoparticles surface (bound to oxygen) and Eu(III) in the core of the nanoparticles (bound to chloride). Glass samples display single-exponential luminescence decays, in which the decay constant approaches the values calculated for the radiative rate constant with Judd-Ofelt analysis. It is concluded that, in sol-gel, mechanisms like electron-phonon coupling suppress the Eu(III) luminescence, which disappear as soon as the nanoparticles are disrupted after heat treatment.