Three alcohol/water-soluble porphyrins, Zn-TPyPMeI: zinc(II) meso -tetra( N -methyl-4-pyridyl) porphyrin tetra-iodide, Zn- TPyPAdBr: zinc(II) meso -tetra[1-(1-adamantylmethyl ketone)-4-pyridyl] porphyrin tetra-bromide and MnCl-TPyPAdBr: man- ganese(III) meso -tetra[1-(1-adamantylmethyl ketone)-4-pyridyl] porphyrin tetra-bromide were employed as cathode interlayers to fabricate polymer solar cells (PSCs). The PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) and PCDTBT (poly[ N -9"- hepta-decanyl-2,7-carbazole- alt -5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)])-blend films were used as active layers in polymer solar cells (PSCs). The PSCs with alcohol/water-soluble porphyrins interlayer showed obviously higher power conversion efficiency (PCE) than those without interlayers. The highest PCE, 6.86%, was achieved for the device with MnCl- TPyPAdBr as an interlayer. Ultraviolet photoemission spectroscopic (UPS), carrier mobility, atomic force microscopy (AFM) and contact angle ( θ ) characterizations demonstrated that the porphyrin molecules can result in the formation of interfacial dipole layer between active layer and cathode. The interfacial dipole layer can obviously improve the open-circuit voltage ( V oc) and charge extraction, and sequentially lead to the increase of PCE.