6533b828fe1ef96bd1287b1a
RESEARCH PRODUCT
Hydrogen-Related Paramagnetic Centers in Ge-Doped Sol-Gel Silica Induced by γ-Ray Irradiation
Aldo MagistrisF. La MattinaSimonpietro AgnelloStefania GrandiRoberto Boscainosubject
Materials scienceSilica gelDopingAnalytical chemistryGeneral ChemistryCondensed Matter PhysicsElectronic Optical and Magnetic Materialslaw.inventionBiomaterialschemistry.chemical_compoundParamagnetismchemistrylawAbsorption bandMaterials ChemistryCeramics and CompositesIrradiationAbsorption (chemistry)Electron paramagnetic resonancesol-gel glasses aerogel germanium doping germanium defects photosensitivityNuclear chemistrySol-geldescription
We have studied the generation mechanisms of H(II) paramagnetic centers in Ge-doped silica by investigating up to 104 mol ppm sol-gel Ge-doped silica materials. We have considered materials with the same concentrations of Ge but that are produced by two different densification routes that give rise to different concentrations of Ge-related oxygen deficient centers (GeODC(II)). These centers are characterized by an optical absorption band at ∼5.2 eV (B2 β band) and two related emissions at ∼3.2 eV and ∼4.3 eV. The GeODC(II) content was estimated by absorption and emission measurements. The H(II) centers were induced by room temperature γ-ray irradiation and their concentration was determined by electron paramagnetic resonance measurements. The comparison between the two kinds of materials, obtained by different preparations, shows that the GeODC(II) concentration increases with the Ge content and is enhanced by vacuum densification. The comparison of irradiated samples shows that beyond the already known process of conversion of preexisting GeODC(II) into H(II) centers, another generation process of H(II) centers is effective that involves irradiation induced GeODC(II).
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2006-01-01 | Journal of Sol-Gel Science and Technology |