Fullerene surfactant compounds useful as interfacial layer in polymer solar cells to enhance solar cell efficiency. Polymer solar cell including a fullerene surfactant-containing interfacial layer intermediate cathode and active layer.
STATEMENT OF GOVERNMENT LICENSE RIGHTS
 This invention was made with Government support under Contract Nos. FA2386-11-1-4072 awarded by the Air Force Office of Scientific Research, N00014-11-1-0300 awarded by the Office of Naval Research, and DE-FC3608GO18024/A000 awarded by the Department of Energy. The Government has certain rights in the invention.