Sol–Gel Synthesis of Rare-Earth and Phosphorus Codoped Monolithic Silica Glasses from a Cosolvent-Free Phase-Separating System

Abstract

A cosolvent-free sol-gel method to prepare monolithic transparent silica glasses doped by rare-earth ions at high concentrations has been developed. Despite the simple solution composition, the reaction mixture undergoes a macroscopic phase separation in parallel with the gelation, and the resultant macropores make it possible to considerably shorten the processing time by facilitating the drying and sintering of gels. The addition of a small amount of phosphorus significantly enhances the dissolution of rare-earth ions, demonstrating a notable effect of phosphorus on the solvation of rare-earth ions in silica glasses. #

Cosolvent-free sol–gel synthesis of rare-earth and aluminum codoped monolithic silica glasses

“…The concentration of Nd 3+ ions corrected for the loss was ³2.0 © 10 20 cm ¹3 for the Al-free glass and ³1.8 © 10 20 cm ¹3 for the Al-codoped glass. It was also found that the loss of Nd 3+ ions from the NdP codoped glass, which we reported previously, 31) was ³9 « 3% and was comparable to that of the Al-free glass. Figure 3 shows XRD patterns of the crushed Al-free and Al-codoped glasses.…”

Recent advances in sol–gel synthesis of monolithic silica and silica-based glasses

“…Despite the high SiOH concentration (∼10 20 cm −3 ), the Tb P codoped glasses exhibit bright green PL under ultraviolet (UV) photoexcitation, as shown in Fig. 11 [136]. The PL decay kinetics is a single exponential, and the PL intensity increases proportionally with Tb to Si molar ratios up to 0.02 (∼5 × 10 4 ppmw or ∼5 wt.% Tb 2 O 3 ), while maintaining the PL decay constant at ∼4.0 ms.…”

“…Reprinted with permission from Ref. [136]; Copyright 2012 The Japan Society of Applied Physics Fig. 12.…”

“…Photograph of various RE P and RE Al codoped silica glasses prepared at RE to Si and P/Al to RE molar ratios of 0.01 and 1, respectively, in the precursor solutions. After Refs [136,137]…”

Effect of CdS nanocrystals on the photoluminescence of Eu3+-doped silicophosphate sol gel glass

“…Phosphorus is employed as a dopant to enhance the dissolution of rare-earth ions in silica glasses. 17 II. Experimental…”