6533b7dafe1ef96bd126d986
RESEARCH PRODUCT
EXAFS studies on the local structure of Er3+ ions in silica xerogels co-doped with aluminium
RoccaF.aFerrariM.aKuzminA.bDaldossoN.cDuvergerC.cMontiF.dsubject
X-RAY-ABSORPTION; GEL GLASS; FLUORESCENCE; silica xerogels; erbiumGEL GLASSMaterials scienceAbsorption spectroscopyExtended X-ray absorption fine structureDopingAnalytical chemistrychemistry.chemical_elementMineralogyCondensed Matter PhysicsSilica xerogelsFluorescenceElectronic Optical and Magnetic MaterialsIonErbiumerbiumchemistryAluminiumX-RAY-ABSORPTIONMaterials ChemistryCeramics and CompositesFLUORESCENCEAbsorption (chemistry)Aluminumdescription
The local environment around Er3+ ions in wet and densified (at 900°C) silica xerogels (pure and co-doped with aluminium) has been studied at the Er L3-edge by X-ray absorption spectroscopy using the fluorescence detection technique. The radial distribution functions (RDF), reconstructed from X-ray absorption fine structure (EXAFS), show several changes in the local co-ordination of erbium ions upon densification: shortening of the Er-O and Er-Si/Al distances, decrease of the co-ordination numbers and broadening of the Er-O RDF. The effect of Al co-doping is clearly discerned by EXAFS in both the first and second co-ordination shells for densified gels and mainly in the second shell for wet gels. For increasing Al content, the interatomic distances between erbium ions and the second co-ordination shell ions become longer and have narrower distribution. A preferential bonding of Er to Al ions is clearly detected, with increasing ordering at higher Al content. EXAFS does not show evidence of a clustering for Er3+ ions after densification: the short range Er-Er co-ordination is absent or not detectable in the present experiments. © 2001 Elsevier Science B.V. All rights reserved.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2001-11-01 |