Influence of Yb Concentration on the Optical Properties of CaF₂ Transparent Ceramics Codoped with Er and Yb

Abstract

Er, Yb:CaF2 nanoparticles with different Yb concentrations were synthesized by a coprecipitation method using nitrates as raw materials. X‐ray powder diffraction and transmission electron microscopy analysis showed that the nanoparticles were single fluorite phase and the nanoparticle size was found to decrease with increasing Yb concentrations. The obtained nanoparticles were hot‐pressed at 800°C under 30 MPa under vacuum environment to fabricate Er, Yb:CaF2 transparent ceramics. The influence of Yb ion concentrations on the optical transmission, microstructure, and luminescence properties of Er, Yb:CaF2 transparent ceramics were investigated. The addition of Yb ions was found effectively to reduce grain size and has a positive effect on improving the optical transmission of Er, Yb:CaF2 transparent ceramics. The highest transmittance in the near‐infrared spectral region of the Er, Yb:CaF2 transparent ceramic reached about 90%. The green, red, and near‐infrared emission intensities were found to increase with increasing Yb concentration.

Influence of preparing conditions on the hot‐pressed sintering of transparent polycrystalline fluorite ceramics

“…Chemically synthesized CaF 2 powders possessing high surface energy and uniform particle size distribution, which are beneficial for the sintering and densifying process. It was reported that the highly transparency fluorite (CaF 2 ) ceramic can be fabricated at 800°C from chemically synthesized powders . As the ball‐milled fluorite powders are much larger than the chemical synthesized CaF 2 powders, optical transparency of polycrystalline ceramics cannot be achieved at 800°C in the study.…”

Nanoscale “fluorescent stone”: Luminescent Calcium Fluoride Nanoparticles as Theranostic Platforms

“…The edge of the fundamental absorption band of CaF 2 lies in the vacuum UV at ca. 12 eV, which makes CaF 2 a transparent matrix in the UV-visible-NIR region and makes CaF 2 a unique luminescent matrix in the study of optical properties of luminescent ions 13,32-38. Figure 2 b shows a typical transparent glasslike CaF 2 :Yb ceramic reported by Mortier's group 32.…”

“…The development of NP-based imaging and therapy has originated a new term; theranostic nanomedicine 9-12. Rare-earth- (RE) doped NPs are particular stars in this category because of the enriched spectral properties of lanthanide ions 13-18. Numerous RE-doped NPs, especially NaYF 4 -related NPs, were synthesized and applied in a wide range of biomedical applications in recent years because of their down/up-conversion luminescence properties 19-24.…”

Upconversion luminescence properties of Ga2O3: Yb3+, Er3+ nanoparticles: Effects of calcination temperature and dopant concentration

“…Also, enhanced green and red upconversion emissions were reported when concentrations of Er 3+ ions were increased in Er doped LiTaO3 [8]. In general, emission intensities have been found to increase with the increase in concentrations of the Yb and Er ions in the codoped system up to an appropriate dopant concentration [1,8,10]. However, higher concentration can induce cross relaxations between dopants which subsequently reduce the efficiency of the UCL [11].…”