A comparative study of co-precipitation and sol-gel synthetic approaches to fabricate cerium-substituted Mg Al layered double hydroxides with luminescence properties

Mg/Al/Ce layered double hydroxides (LDHs) intercalated with carbonate and hydroxide anions were synthesized using co-precipitation and sol-gel method. The obtained materials were characterized by thermogravimetric (TG) analysis, X-ray diffraction (XRD) analysis, fluorescence spectroscopy (FLS) and scanning electron microscopy (SEM). The chemical composition, microstructure and luminescent properties of these LDHs were investigated and discussed. The Ce3 + substitution effects were investigated in the Mg3Al1 − xCex LDHs by changing the Ce3 + concentration in the metal cation layers from 0.05 to 10 mol%. It was demonstrated, that luminescence properties of cerium-substituted LDHs depend on the morphological features of the host lattice.publishe

Sol-gel synthesis and characterization of non-substituted and europium- substituted layered double hydroxides Mg3/Al1-xEux

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Yellow persistent luminescence of Sr2SiO4:Eu2+,Dy3+

This paperreportsthephotoluminescenceandafterglowofSr2SiO4 doped withEu2þ and Dy3þ. Factors governingtheformationofthemonoclinicororthorhombicphaseofthisortho-silicatearedescribed and theimpactofthecrystallographicmodificationontheluminescenceandafterglowunderUVand VUV excitationarediscussedandinsightinfactorslimitingtheefficiencyofthisyellowafterglow materialisgiven

Yellow persistent luminescence of Sr2SiO4:Eu2+,Dy3+

This paperreportsthephotoluminescenceandafterglowofSr2SiO4 doped withEu2þ and Dy3þ. Factors governingtheformationofthemonoclinicororthorhombicphaseofthisortho-silicatearedescribed and theimpactofthecrystallographicmodificationontheluminescenceandafterglowunderUVand VUV excitationarediscussedandinsightinfactorslimitingtheefficiencyofthisyellowafterglow materialisgiven

Luminescence and Luminescence Quenching in Gd3(Ga,Al)5O12 Scintillators Doped with Ce3+

The optical properties of gadolinium gallium aluminum garnet, Gd3(Ga,Al)5O12, doped with Ce3+ are investigated as a function of the Ga/Al ratio, aimed at an improved understanding of the energy flow and luminescence quenching in these materials. A decrease of both the crystal field strength and band gap with increasing content of Ga3+ is observed and explained by the geometrical influence of Ga3+ on the crystal field splitting of the 5d level in line with theoretical work of Muñoz-García et al. (Muñoz-García, A. B.; Seijo, L. Phys. Rev. B 2010, 82, 184118). Thermal quenching results in shorter decay times as well as reduced emission intensities for all samples in the temperature range from 100 to 500 K. An activation energy for emission quenching is calculated from the data. The band gap of the host is measured upon Ga substitution and the decrease in band gap is related to Ga3+ substitution into tetrahedral sites after all octahedral sites are occupied in the garnet material. Based on the change in band gap and crystal field splitting, band diagrams can be constructed explaining the low thermal quenching temperatures in the samples with high Ga content. The highest luminescence intensity is found for Gd3(Ga,Al)5O12 with 40% of Al3+ replaced by Ga3+

«Étude des propriétés de luminescence d’oxydes La₂Ti₂O₇ substitués ou co-substitués par des lanthanides»

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