Understanding the Reduced Efficiencies of Organic Solar Cells Employing Fullerene Multiadducts as Acceptors - Faist, MA; Shoaee, S; Tuladhar, S; Dibb, GFA; Foster, S; Gong, W; Kirchartz, T; Bradley, DDC; Durrant, JR; Nelson, J (ADVANCED ENERGY MATERIALS, 2013)