Silica spheres were prepared by the Stober method, and the method of labeli
ng with pyrene, using aminopropylysilane as the linking agent, was optimize
d. Excimers between particles were formed when high concentrations of label
were used. Both surfactant and polyelectrolyte addition were able to cause
hoc formation when added to suspensions of the silica, but only the surfac
tant changed the I-1/I-3 ratio and diminished excimer formation. (C) 2000 A
cademic Press.