Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
BCSJ Award Article
Cosolvent-Free Sol–Gel Synthesis and Optical Characterization of Silica Glasses Containing LaF3 and (La,Er)F3 Nanocrystals
Kotomi SuzukiKoichi KajiharaKiyoshi Kanamura
Author information
JOURNALS FREE ACCESS

2014 Volume 87 Issue 7 Pages 765-772

Details
Abstract

Monolithic transparent silica glasses containing LaF3 nanocrystals were prepared by a cosolvent-free sol–gel method based on the pyrolysis of lanthanum trifluoroacetate. The two-step mixing of alkoxide and water, consisting of partial hydrolysis under acidic conditions and subsequent neutralization to catalyze the polycondensation of hydrophobic silica oligomers, makes it possible to shorten the processing time while eliminating the need for cosolvents. The size of the LaF3 nanocrystals decreases with an increase in the volume fraction of LaF3. This suppresses Rayleigh scattering and improves transparency at LaF3-rich compositions. Green and red upconversion photoluminescence (PL) bands, mainly caused by energy-transfer upconversion (ETU), are observed in Er-doped samples under excitation at 980 nm. The PL intensity drastically increases with an increase in the volume fraction of the LaF3 phase as a result of improved crystallinity of LaF3. The quantum yields recorded for the green and red upconversion PL bands were ca. 0.08% and ca. 0.04%, respectively.

Monolithic transparent silica glasses containing LaF3 nanocrystals were prepared by a cosolvent-free sol–gel method based on the pyrolysis of lanthanum trifluoroacetate. In Er-doped samples visible upconversion photoluminescence (PL) caused by energy-transfer upconversion (ETU) is observed under excitation at 980 nm. All of the size of the LaF3 nanocrystals, the Rayleigh scattering intensity, and the nonradiative decay rate decrease with an increase in the volume fraction of LaF3. Fullsize Image
 
Information related to the author

This article cannot obtain the latest cited-by information.

© 2014 The Chemical Society of Japan
Previous article Next article
feedback
Top