Methanofullerenes, C6o(CH2)n (n=1, 2, 3), as Building Blocks for High-Performance Acceptors Used in Organic Solar Cells

Selective preparation of C-60(CH2)n (n = 1, 2, 3) was realized via a Bingel-decarboxylation route. A 54 pi-electron derivative of C-60(CH2)(2), OQBMF, demonstrates an outstanding power conversion efficiency (PCE) of 6.43% (V-oc = 0.95 V, J(sc),c = 9.67 mA cm(-2), FF = 70%) in fullerene:P3HT solar cells since the small CH2 addends lift up fullerene LUMO and increase V-oc, significantly without decreasing mobility significantly.