The photoelectrical properties of p-n junction organic solar cells based on C-60 and phthalocyanines (mainly oxotitanium(IV) phthalocyanine (OTiPc)) were investigated. With the Al/C-60/OTiPc/ITO configuration, the energy conversion efficiencies (eta) are high at low incident Light intensities (P-in), due to the formation of a p-n junction between C-60 and OTiPc, but decrease with an increase in P-in. On the other hand, ITO/C-60/OTiPc/Cr . Au cells are stable even under white-light illumination at high P-in. It was found that the insertion of an SiO2 insulator layer between OTiPc and Cr . Au significantly enhances the short-circuit current, the open-circuit voltage and eta.