Function of CH2 Addends on 54π Fullerene Acceptors

Three structurally analogous 54 pi fullerene acceptors, tris-o-quinodimethane-C-60 (tris-OQC), bis-o-quinodimethanemethanon[60] fullerene (bis-OQMF), and o-quinodimethane-bis-methano[60] fullerene (OQBMF), were systematically investigated. As o-quinodimethane addends on C-60 are replaced stepwise by methylene groups (CH2), the electron mobility of fullerene, the crystallinity of poly(3-hexylthiophene), and the morphology of the active layer of solar cells were simultaneously improved while bimolecular recombination in the active layer was reduced, leading to a remarkable enhancement in power conversion efficiency.