Phase-Transition-Driven Regional Distribution of Rare-Earth Ions for Multiplexed Upconversion Emissions.

Phase transition of the polymorphs is critical for controlled synthesis and property modulation of functional materials. Upconversion emissions from an efficient hexagonal sodium rare-earth (RE) fluoride compound, β-NaREF, which is generally obtained from the phase transition of the cubic (α-) phase counterpart, are attractive for photonic applications. However, the investigation of the α → β phase transition of NaREF and its effect on the composition and architecture is still preliminary.

Crystallization of GdO nanoparticles: evolution of the microstructure via electron-beam manipulation.

NaGdF4 is one of the most commonly employed phosphor host matrices for lanthanide doping and is one of the most efficient infrared-to-visible up-conversion fluorescent host materials. Although the structure, morphology and luminescence properties of NaREF4 have been sufficiently investigated, there are very few reported instances of introducing localized order/crystallinity by electron-beam (e-beam) irradiation. In this work, we studied the phase transformation of Gd2O3 from an amorphous to crystalline form via manipulation by e-beam irradiation.

Unravelling the energy transfer of Er-self-sensitized upconversion in Er-Yb-Er clustered core@shell nanoparticles.

Unravelling upconversion (UC) energy transfer mechanisms is significant for designing novel efficient anti-Stokes phosphors. We have studied the correlation of different lanthanide dopants within Er-self-sensitized core@shell upconversion nanoparticles (UCNPs). Here, our focus will be on high-concentration dopants that are able to sufficiently produce the clustering effect, especially within the interplay between Er and Yb.