Papers by Keyword: BaF₂

Abstract: Yb³⁺and Er³⁺ co-doped BaF₂ phosphors were prepared by high temperature solid reaction method. Effects of mol content ratios of Yb³⁺ ion to Er³⁺ion (CYb3+∶CEr3+) and charge compensation agent Na₂SiF6 contents on the up-conversion luminescence of the samples were studied. The XRD and PL were carried out to investigate the phases and the up-conversion luminescence. Three up-conversion emissions were observed with peaks at 460nm, 548nm and 660nm respectively. The up-conversion luminescence intensity increases firstly, and then decreases with increasing CYb3+∶CEr3+ and the optimal ratio was found to be at 12:2 with fixed Er³⁺ contents 2mol%. The up-conversion emission intensity was enhanced by introducing Na₂SiF6 as the charge compensation agents and its optimal content was found to be 2mol%.

Abstract: Materials with an average particle size of less than about 50 nm often show new or at least enhanced physical properties. In many cases nanocrystalline ionic conductors exhibit a high increase of cation, e. g. Li+, or anion, e. g. F−, diffusivity. In the present contribution we review recent studies on ion dynamics in nanocrystalline ion conductors, both single-phase systems and composites, being prepared by high-energy ball milling. These include, e.g., LiTaO3, Li2O:Al2O3, LiF:Al2O3, BaF2, CaF2, BaF2:CaF2 and (BaF2:CaF2):Al2O3. Dynamic properties were probed by 7Li and/or 19F NMR line shape and relaxation as well as ion conductivity measurements.