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Structural, photoluminescent properties and Judd-Ofelt analysis of Eu3+-activated CaF2 nanocubes.
- Source :
-
Journal of Alloys & Compounds . Jan2020, Vol. 813, pN.PAG-N.PAG. 1p. - Publication Year :
- 2020
-
Abstract
- Eu3+-doped CaF 2 nanocubes with variable europium concentration, [Eu3+] = 0, 0.6, 1.3, 1.7, 2.2 and 5.4 mol%, have been synthesized by a direct precipitation route. It has been found that, within this concentration range, the nanoparticles present the fluoride-type crystalline structure and the characteristic cubic shape of CaF 2 crystals. The nanoparticle size follows a log-normal distribution with a mean value decreasing with the Eu3+ content. Rietveld refinement has been performed to calculate the lattice parameter and crystallite size. Eu3+ concentration affects both parameters giving rise to an increase in the lattice parameter and a reduction of crystallite size. The luminescent properties of Eu3+ ions in these nanostructures have been investigated under CW and pulsed excitation. A Judd-Ofelt analysis, as function of the Eu3+ content, has been performed to determine the transition probabilities, radiative lifetimes and branching ratios of the 5D 0 emitting level. It was found that Ω 2 and Ω 4 Judd-Ofelt intensity parameters are dependent on the doping level, showing an evolution that indicates a decrease in the Eu3+ site local symmetry with increasing Eu3+ concentration. Finally, it has been observed that the characteristic luminescence decay time of the 5D 0 manifold is reduced with increasing Eu3+ concentration. This effect is partially due to an increase of radiative transition probability, associated with a reduction in the local symmetry of the lanthanide ions, and also to the occurrence of concentration quenching effects. Image 1 • High CaF 2 :Eu3+ nanocubes. • Eu3+ excellent probe to link structural and luminescence properties. • Judd-Ofelt analysis dependent on structural properties. • Optimum doping level at 2 mol% europium concentration. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09258388
- Volume :
- 813
- Database :
- Academic Search Index
- Journal :
- Journal of Alloys & Compounds
- Publication Type :
- Academic Journal
- Accession number :
- 139143153
- Full Text :
- https://doi.org/10.1016/j.jallcom.2019.152194