Morphology control of organic luminescent microcrystals and approach of their optical properties

Microcrystals of an organic fluorescent dye, 4-octylamino-7-nitrobenz-2-oxa-1,3-diazole, were prepared using a reprecipitation method, based on solvent-exchange. We show here that their shape and size can be nicely tuned by the presence of various macromolecules in the reprecipitation medium. To do so, poly(acrylic acid) and calf thymus DNA were used as additives. Homogeneous populations of microcrystals were thus obtained in a reproducible way. Their size and morphology varied with the additive used. The UV/vis absorption and luminescence properties of these microcrystals in suspension are briefly reported. To cite this article: M. Abyan et al., C. R. Chimie 8 (2005).