Four different types of heterojunction organic solar cells were fabricated by using C70 and C60 as the electron acceptor and Rubrene and CuPc as the electron donor.The experimental results reveal that the short-circuit current(Jsc) of the organic solar cells with C70 instead of C60 as acceptor is increased significantly,while the open-circuit voltage(Voc) of the organic solar cells with Rubrene instead of CuPc as donor is increased greatly.The Voc,Jsc,fill factor(FF) and power conversion efficie...