A case study of energy transfer mechanism from uranium to europium in ZnAl₃O₄ spinel host by photoluminescence spectroscopy

Microwave-Assisted Hydrothermal Synthesis of Zinc-Aluminum Spinel ZnAl2O4

The drawback of the hydrothermal technique is driven by the fact that it is a time-consuming operation, which greatly impedes its commercial application. To overcome this issue, conventional hydrothermal synthesis can be improved by the implementation of microwaves, which should result in enhanced process kinetics and, at the same time, pure-phase and homogeneous products. In this study, nanometric zinc aluminate (ZnAl₂O₄) with a spinel structure was obtained by a hydrothermal method using microwave reactor. The average ZnAl₂O₄ crystallite grain size was calculated from the broadening of XRD lines. In addition, BET analysis was performed to further characterize the as-synthesized particles. The synthesized materials were also subjected to microscopic SEM and TEM observations. Based on the obtained results, we concluded that the grain sizes were in the range of 6-8 nm. The surface areas measured for the samples from the microwave reactor were 215 and 278 m² g^-1.

White light emission from co-doped La2Hf2O7 nanoparticles with suppressed host → Eu3+ energy transfer via a U6+ co-dopant

This work highlights white light emission from La₂Hf₂O₇:Eu³⁺ nanoparticles assisted by uranium co-doping to restrict energy transfer from the host oxygen vacancy to the Eu³⁺ dopant.