Study on the fluorescence properties of fluorescein dye incorporated into SBA-15

Fluorescein was first introduced to the large pore channel of SBA-15 by impregnation method. UV-Vis absorption, fluorescence emission and lifetime were used to characterize the host-guest composite. The existing forms of fluorescein in SBA-15 consist of monoanion and dianion. The emission spectrum of fluorescein in SBA-15 shifts to blue about 10 nm and the fluorescence lifetime is largely prolonged compared with that in ethanol. The prolonged lifetime in SBA-15 is attributed to the high dispersion of fluorescein molecules in SBA-15 and the formation of hydrogen bond with silanols on the surface of SBA-15. (c) 2005 Elsevier B.V. All rights reserved.