PCBM is the common abbreviation for the fullerene derivative, [6,6] phenyl-C61-butyric acid methyl ester and is one of the most commonly used electron-accepting materials in organic photovoltaic devices.

It is commonly used in flexible plastic or electronic solar cells in conjunction with an electron donor material such as P3HT (SOL4106), PCDTBT (SOL4280) or PTB7 (SOL4700) to make high Open Circuit Voltage (Voc), high Power Conversion Efficiency (PCE) bulk heterojunction solar cells, >99.9% [6,6] isomerized.

It is a more practical choice for being an electron acceptor when compared to fullerenes due to its solubility in chlorobenzene. This allows for processable donor/acceptor solution mixtures, a necessary property for “printable” solar cells.