PCBM ([6,6]-phenyl-C61-butyric acid methyl ester) is a fullerene derivative being investigated for its potential use in organic solar cells.

[3] PCBM is a fullerene derivative of the C60 buckyball that was first synthesized in the 1990s.

It is a more practical choice for an electron acceptor when compared with fullerenes because of its solubility in chlorobenzene.

This allows for solution processable donor/acceptor mixes, a necessary property for "printable" solar cells.

However, considering the cost of fabricating fullerenes, it is not certain that this derivative can be synthesized on a large scale for commercial applications.