Enhancement of Fluorescent Intensity of a SiO2 : Sm Glass by Al Codoping and Local Structure around Sm by an EXAFS Study

Abstract

A1 codoped SiO2:Sm phosphors were prepared by the alkoxide method, which starts from a hydrolysis of silicon ethoxide and the metal nitrates at low temperature and minimizes the contamination of impurities. An addition of A1 ions to SiO~:Sm is found to increase emission intensity from Sm ion more than an order of magnitude. EXAFS study revealed that local structures around Sm ions in the phosphors with and without dopant are significantly different; in the SiO2:Sm phosphor Sm atoms are well dispersed at low Sm concentrations and Sm atoms agglomerate at high concentrations, while in the A1 codoped phosphor Sm atoms are coordinated by A1 through Sm-O-A1 bonding. This provides a direct structural evidence of the role of the codopant. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 137.99.31.134 Downloaded on 2015-05-26 to IP

Luminescence and variation of valent state for cerium within pores of mesoporous silica

“…Ce 4+ -doped glasses should be subjected to reduction treatment so that luminescence occurs. Only when the Ce 3+ ion is doped into a silica network does the effect of the crystal field on cerium lead to luminescence [2,3]. In this study, however, instead of directly doping cerium into a silica network, we put the Ce 4+ and Ce 3+ ions into pores of mesoporous silica by soaking and investigate their luminescence and variation of valent state.…”