Optical Characterization of Nano- and Microcrystals of EuPO4 Created by One-Step Synthesis of Antimony-Germanate-Silicate Glass Modified by P2O5

Abstract

Abstract:Technology of active glass-ceramics (GC) is an important part of luminescent materials engineering. The classic method to obtain GC is based on annealing of parent glass in proper temperature and different time periods. Generally, only the bulk materials are investigated as a starting host for further applications. However, the effect of an additional heat-treatment process on emission and structural properties during GC processing is omitted. Here, we focus on the possibility of obtaining transparent glass-ceramic doped with europium ions directly with a melt-quenching method. The influence of phosphate concentration (up to 10 mol %) on the inversion symmetry of local environment of Eu 3+ ions in antimony-germanate-silicate (SGS) glass has been investigated. The Stark splitting of luminescence spectra and the local asymmetry ratio estimated by relation of ( 5 D 0 → 7 F 2 )/( 5 D 0 → 7 F 1 ) transitions in fabricated glass confirms higher local symmetry around Eu 3+ ions. Based on XRD and SEM/EDX measurements, the EuPO 4 nano-and microcrystals with monoclinic geometry were determined. Therefore, in our experiment, we confirmed possibility of one-step approach to fabricate crystalline structures (glass-ceramic) in Eu-doped SGS glass without additional annealing process.

Luminescent Studies on Germanate Glasses Doped with Europium Ions for Photonic Applications

“…Based on these changes, the asymmetric ratio (AR) intensities, defined as the relation of the electric dipole transition ( 5 D 0 → 7 F 2 ) to the magnetic dipole transition ( 5 D 0 → 7 F 1 ), were estimated (inset in Figure 8). The value of the ( 5 D 0 → 7 F 2 )/( 5 D 0 → 7 F 1 ) transition ratio gives a factor of the degree of structural distortion from the inversion symmetry of the local environment of the europium ions [39]. We observed that replacing the BaO by P 2 O 5 up to 20 mol.% leads to a decrease of the asymmetric ratio, which is related to the partial structural arrangement in the ligand field around Eu 3+ ions.…”

“…The phosphorous oxide is characterized by high phonon energy (1200 cm −1 ) and reduces clustering effects via non-bridging oxygen formation, better incorporating rare earth ions promoting more efficient emissions than pure germanate glasses [37]. Even more interesting is that the P 2 O 5 can be used as a nucleating agent for transparent glass-ceramic materials [38,39]. In view of the above, it is important to find a suitable composition of germanate glass that might be potentially used to produce the glass-ceramic material with functionalized luminescent properties.…”

Crystallization Mechanism and Optical Properties of Antimony-Germanate-Silicate Glass-Ceramic Doped with Europium Ions

“…Based on our earlier investigations, SGS glass was chosen for this investigation because of its good thermal stability, and low phonon energy glass matrix, which can improve quantum efficiency and probability of radiative transitions for electrons of rare-earth ion dopant [ 4 , 6 , 30 ]. Another reason was the possibility of shaping SGS into optic fibers.…”

“…This research analyzed the effect of P 2 O 5 concentration on the luminescence spectra, asymmetry ratio (AR), and luminescence decay. Due to earlier work [ 30 ], we decided to limit the P 2 O 5 concentration up to 1 mol%, and we mainly focused on investigating the crystallization process in antimony-germanate-silicate glass, enabling size and density control of EuPO 4 nanocrystals. The main objective of this experiment was to obtain a good optical quality core material as an 11 mm dia rod with specific crystalline properties and crystallization conditions.…”

Nanocomposite Antimony-Germanate-Borate Glass Fibers Doped with Eu3+ Ions with Self-Assembling Silver Nanoparticles for Photonic Applications

“…The advantage of the Eu 3+ ion is also its common use as a spectroscopic probe of the site symmetry in different host matrices [9,10]. The main approach relies on the analysis of the intensity ratio of electrical-dipole (ED: 5 D 0 → 7 F 2 ) to magnetic-dipole (MD: 5 D 0 → 7 F 1 ) transitions, which determines the asymmetry of the ligand environment and the covalency of metal-ligand bond [11,12].…”