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Inorganic and organically modified rare‐earth‐doped silica gels
Author(s) -
Stone Brandon T.,
Costa Vilma C.,
Bray Kevin L.
Publication year - 1997
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690431325
Subject(s) - fluorescence , doping , sol gel , rare earth , silica gel , chemistry , materials science , nuclear chemistry , inorganic chemistry , analytical chemistry (journal) , mineralogy , chromatography , nanotechnology , physics , optoelectronics , quantum mechanics
The fluorescence properties of inorganic and organically‐modified rare‐earth‐doped sol‐gel silica are presented. Eu 3+ ‐doped ormosils were prepared from Si(OCH 3 ) 4 and CH 3 Si(OCH 3 ) 3 , (CH 3 ) 2 Si(OCH 3 ) 2 , (CH 3 ) 2 Si(OC 2 H 5 ) 2 , or (n‐C 3 H 7 )Si(OCH 3 ) 3 in various proportions. Er 3+ ‐doped ormosils were prepared using Si(OC 2 H 5 ) 4 and CH 3 Si(OC 2 H 5 ) 3 , (CH 3 ) 2 Si(OC 2 H 5 ) 2 or C 2 H 5 Si(OC 2 H 5 ) 3 . Gels derived from Si(OCH 3 ) 4 were also doped with the fluorinated Eu 3+ precursors Eu(fod) 3 , (CF 3 SO 3 ) 3 Eu, and (CF 3 CO 2 ) 3 Eu·3H 2 O. The effect of metal ion codopants, which are known to inhibit clustering of Eu 3+ in sol‐gel silica, on Er 3+ fluorescence is also considered. Fluorescence line‐narrowing studies of Eu 3+ ‐doped samples indicated that significant Eu 3 clustering occurs in both the ormosils and fluorinated precursor compositions. Lifetime measurements of the Eu 3+ ‐and Er 3+ –doped ormosils showed longer lifetimes at low heat treatment temperatures relative to purely inorganic sol‐gel silica, but no significant difference remained in fully densified samples. The longest lifetimes were observed for samples doped with the fluorinated precursors, indicating that the fluorinated ligands are effective at reducing the water content in densified gels.