The optical limiting properties of fullerene derivatives containing silicon alkoxide functionalities are measured in toluene solution both at 532.0 and 652.0 nm and compare favourably with those of Ca.

The optical-limiting properties of a series of novel [60]fullerene derivatives have been investigated in toluene solutions and in sol ± gel glasses. Working at different wavelengths, it is found that the efficiency of the new compounds compares well with that of pristine C 60 . In particular, better performance of the organofullerenes is obtained when the pumping wavelength approaches the triplet ± triplet absorption maximum of the derivatives at % 700 nm. The main component in the optical-limiting behavior is, in fact, ascribed to a reverse saturable absorption mechanism. A relevant feature in the structure of the new organofullerenes is that a silicon-alkoxide moiety is covalently attached to C 60 . This guarantees the grafting of the fullerene spheroid to the silicon matrix during the sol ± gel process. Some of the derivatives show remarkable solubility in THF, a solvent widely used in sol ± gel processing, in which C 60 is itself insoluble.