The time-resolved studies on the fluorescence properties of Fe2O3 nanoparti
cles prepared by forcing hydrolysis and microemulsion techniques were carri
ed out for the first. time. Two different systems of different sized nanocr
ystals were characterized. Specifically Fe2O3 5, 10 and 20 nm particles in
water and Fe2O3 5, 10 nm particles in toluene demonstrated different fluore
scence behavior. We discussed the observed phenomena in terms of surface re
lated effects, attributing the crucial role in optical time response to the
surface polarization in these systems. At the same time we clarify some co
ntroversial conclusions made in other related studies. (C) 2000 Elsevier Sc
ience Ltd. All rights reserved.