Effect of dopant precursors on the optical properties of rare‐earths doped oxyfluoride glass‐ceramics

Abstract

The crystallization of fluoride nanocrystals (NCs) in chemically and mechanically stable aluminosilicate glasses has shown interesting optical properties even for small crystal fractions (10‐15 wt%). When rare‐earth (RE) ions are used as dopants, crystal‐like features can be reproduced and an increase in the emission and/or energy transfer processes, with respect to the starting glasses, is observed. A crucial point for these materials is the study of the local surrounding of RE ions and their incorporation in the NCs. In fact, the effective concentration in the NCs can be much higher than the nominal concentration, up to one order of magnitude or even higher. The knowledge of RE ions incorporation in the NCs permits choosing proper doping levels to optimize both linear and nonlinear optical properties. In this work, transparent oxyfluoride glass‐ceramics with LaF3 NCs, doped with Nd3+ and Er3+ using oxide and fluoride precursors, were prepared using the melt‐quenching method and controlled crystallization. The local surrounding of the RE ions was studied using X‐ray absorption spectroscopy, electron paramagnetic resonance and photoluminiscence. The results show that most RE ions are already in a fluorine‐rich amorphous environment even in the initial glass. The crystallization process provokes the RE ion redistribution and incorporation in the fluoride NCs. The different RE precursors, used as oxides or fluorides, have an influence on the incorporation of the RE in the NCs and, as a consequence, on the final optical properties.

Fluorine in Complex Alumino-Boro-Silicate Glasses: Insight into Chemical Environment and Structure

“…Various glass oxyfluoride systems are also important for optical and photonic applications, , including glass ceramics with F-containing optically active crystals − and rare-earth fluoride-containing systems for lasers . Of the oxyfluoride glass-forming systems that have been investigated, including silicate and borate systems, perhaps the most important for optics has been fluoride-containing phosphate glasses. , …”

Photoelectric properties of glass-ceramics containing KTb2F7 nanocrystals for UV detection

“…It is found that most of the RE ions are concentrated in the uorine-rich amorphous regions in the parent glass, and the crystallization process triggers the redistribution and incorporation of RE ions in uoride nanocrystals. 31 Herein, a novel Tb 3+ doped uorosilicate glass is synthesized by melt-quenching method, and KTb 2 F 7 nanocrystals are precipitated from the glass via the subsequent heat-treatment. The microstructure and optical properties of GC containing KTb 2 F 7 nanocrystals are investigated by X-ray diffraction (XRD) patterns, transmission electron microscopy (TEM) images, transmission spectra, photoluminescence spectra, Raman spectra and FTIR spectra.…”

“…It is found that most of the RE ions are concentrated in the fluorine-rich amorphous regions in the parent glass, and the crystallization process triggers the redistribution and incorporation of RE ions in fluoride nanocrystals. 31…”