10 cm(2) area molecular photovoltaic cells have been fabricated, incorporating transparent protection layers of naphthalene tetracarboxylic anhydride (NTCDA), completely suppressing electrical shorting. Even a 2 mu m-thick NTCDA layer was unable to degrade cell performance. Three-layered organic solar cells incorporating a codeposited interlayer of fullerene and metal-free phthalocyanine, whose nanostructure was optimized by controlling the substrate temperature during coevaporation, showed a photoelectric conversion efficiency of 2.5% under illumination with simulated solar light. The three-layered cells were concluded to have a p-i-n energetic structure.