New approach for forming bulk-heterojunction solar cells comprising a π-conjugated polymer and C60

A new approach for high-efficiency polymer solar cells utilizing a BHJ active layer consisting of poly(3-hexylthiophene) (P3HT) as a donor and buckminsterfullerene, C60 as an acceptor was demonstrated. P3HT/C60 BHJ films were made possible by in situ formation of C60 from solubilized addends, C60–CpCO2R (R = Hex, Oct, and EHex) by retro Diels–Alder reaction at, or above, 100 °C. These cells exhibit enhanced performances compared to as-prepared P3HT/C60 BHJ films, showing better morphology.