[60]IPB is a fullerene derivative of C60 which is used as an electron acceptor material in organic photovoltaic (OPV) solar cells. Comparing with PCBMs,?[60]IPX (where X is either B, butyl, H, hexyl, or O, octyl) fullerenes give about 50 mV higher open circuit voltage (VOC). It has been reported that in P3HT?solar cells, the efficiency is increased by 10-15% compared to [60]PCBM [1].