Here we report a comparative study of seven different cyclopropane-type bisadducts (represented by mixtures of multiple isomers) in organic bulk heterojunction solar cells using poly(3-hexylthiophene) (P3HT) as a donor polymer. It was shown that the material solubility affects both the composite morphology and the photovoltaic performance. A good correlation between the solubility of the fullerene derivatives and parameters of solar cells has been revealed. (C) 2013 Elsevier B.V. All rights reserved.