Surface modification on time-resolved fluorescences of Fe2O3 nanocrystals

The time-resolved studies on the fluorescence properties of Fe2O3 nanoparticles prepared by forcing hydrolysis and microemulsion techniques were carried out for the first. time. Two different systems of different sized nanocrystals were characterized. Specifically Fe2O3 5, 10 and 20 nm particles in water and Fe2O3 5, 10 nm particles in toluene demonstrated different fluorescence behavior. We discussed the observed phenomena in terms of surface related effects, attributing the crucial role in optical time response to the surface polarization in these systems. At the same time we clarify some controversial conclusions made in other related studies. (C) 2000 Elsevier Science Ltd. All rights reserved.