Abstract

Materials containing a spherical π-electron moiety have the added advantage of enhanced intermolecular interactions. Buckminsterfullerene is a special spherical π-electron carbon cluster which, unfortunately, is only sparingly soluble in most common solvents. It is therefore imperative that the cluster be derivatized (functionalized) to be incorporated into most familiar solids for materials science applications.

Addition and cycloaddition reactions are the only synthetic methods available to functionalize C₆₀. Of these, the so called Bingel, Bingel–Hirsch, Prato and azoalkane cycloaddition reactions are the most useful and have been used over the past decade to produce a myriad of C₆₀-based molecules as well as many materials.

So far, there are only two areas where functionalized fullerenes have had an impact: plastic solar cells and optical limiting glasses, with lesser applications in polymeric materials and fullerene-modified traditional materials. The emphasis of this article is therefore on photodiodes and optical limiting glasses.