Search

We present a crack-free optically active SiO 2 glass-composite material containing YAG:Ce synthesized via a modified sol-gel technique. A glass-composite material consisting of yttrium aluminum garnet doped with Ce 3+ (YAG:Ce) was entrapped into a SiO 2 xerogel. This composite material was prepared using a sol-gel technique with modified gelation and a drying process to obtain crack-free optically active SiO 2 glass. The concentration of the YAG:Ce was from 0.5 to 2.0 wt%. All synthesized samples were characterized via X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, confirming their exceptional quality and structural integrity. The luminescence properties of the obtained materials were studied. Overall, the prepared samples' excellent structural and optical quality makes them great candidates for further investigation, or even potential practical application. Furthermore, boron-doped YAG:Ce glass was synthesized for the first time.

We report the procedure for hydrothermal synthesis of ultrasmall Yb 3+ /Tm 3+ co-doped Sr 2 LaF 7 (SLF) upconversion phosphors. These phosphors were synthesized by varying the concentrations of Yb 3+ (x = 10, 15, 20, and 25 mol%) and Tm 3+ (y = 0.75, 1, 2, and 3 mol%) with the aim to analyze their emissions in the near IR spectral range. According to the detailed structural analysis, Yb 3+ and Tm 3+ occupy the La 3+ sites in the SLF host. The addition of Yb 3+ /Tm 3+ ions has a huge impact on the lattice constant, particle size, and PL emission properties of the synthesized SLF nanophosphor. The results show that the optimal dopant concentrations for upconversion luminescence of Yb 3+ /Tm 3+ co-doped SLF are 20 mol% Yb 3+ and 1 mol% Tm 3+ with EDTA as the chelating agent. Under 980 nm light excitation, a strong upconversion emission of Tm 3+ ions around 800 nm was achieved. In addition, the experimental photoluminescence lifetime of Tm 3+ emission in the SLF host is reported. This study discovered that efficient near IR emission from ultrasmall Yb 3+ /Tm 3+ co-doped SLF phosphors may have potential applications in the fields of fluorescent labels in bioimaging and security applications., Competing Interests: The authors declare no conflicts of interest.

Yttrium aluminum garnet doped with europium with an additional impurity phase of yttrium vanadate doped europium has been prepared in different ways: synthesized by a sol-gel route and mechanically mixed in a mortar. The obtained samples were characterized by X-ray diffraction analysis, and scanning electron microscopy. Photoluminescence spectra were recorded to understand the role of the impurity phase in the garnet's optical properties. The impurity phase showed a significant contribution to the optical properties of Y 3 Al 5 O 12 :1%Eu., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)