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International Journal of Photoenergy
Volume 2006, Article ID 30937, 5 pages

Free-standing microcrystals of a fluorescent organic dye: Preparation and spectroscopic study

Laboratoire des Interactions Moléculaires Réactivité Chimique et Photochimique, UMR CNRS 5623, Université Paul Sabatier, Toulouse Cedex 9 31062, France

Received 25 February 2005; Accepted 7 June 2005

Copyright © 2006 Mouhammad Abyan 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.


Suspensions of microcrystals were obtained from an organic fluorescent dye, 4-n-octylamino-7-nitrobenz-2-oxa-1,3-diazole, by reprecipitation in water in the presence of various macromolecules: anionic or cationic PAMAM dendrimer, poly(acrylic acid, sodium salt), poly(acrylamide), and calf thymus DNA. The use of these additives allowed the size and shape of the microcrystals to be controlled. A study by UV/vis absorption and fluorescence spectroscopy revealed some common points, but also some interesting differences, in the optical behaviour of the five samples.