In this paper,LiF,tris(8-hydroxyquinolato) aluminum(Alq 3) and zinc phthalocyanine(ZnPc) were used as cathode modification materials in small molecular organic solar cells based on ZnPc/C 60 structure,and their influence on the characteristics and stabilities was investigated.It is found that the devices with appropriate thicknesses of buffer layers show better performance than those with the unmodified ones.The devices′ stabilities have been greatly improved.Different modified materials show di...