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Research Letters in Materials Science
Volume 2007, Article ID 23018, 5 pages
http://dx.doi.org/10.1155/2007/23018
Research Letter

Structural Effects of Heat-Treated Silica Xerogel Induced by Incorporation of Chlorophyll Species

1Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, Mexico
2Departamento de Físico-Matemáticas, Universidad Autónoma de San Luis Potosí, 78000 San Luis Potosí, Mexico

Received 29 August 2007; Accepted 5 October 2007

Academic Editor: G. Q. Lu

Copyright © 2007 J. R. Martínez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Composites containing chlorophyll aggregates dispersed in amorphous silica are of interest because of their optical attractive properties. The silica powders added with chlorophyll species, prepared by the sol-gel method, were studied using X-ray diffraction, IR spectroscopy and differential temperature analysis. Silica xerogel samples were prepared using an ethanol/H2O/TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of the annealing temperature. We found in our samples partial crystallization of the glass matrix in form of tridymite and cristobalite phases and quenching centers or nonfluorescing aggregates due to denaturation of photosystem promoted by chlorophyll decomposition after 400C.