Transparent conductive oxide-less back contact dye-sensitized solar cells using Zinc porphyrin dye employing cobalt complex redox shuttle

A transparent conductive oxide-less (TCO-less) dye-sensitized solar cell (DSSC) consisting of back-contacted stainless steel metal mesh electrode has been fabricated. In this work, [Co(bpy)₃]^3+/2+ complex based redox electrolyte and porphyrin dye as sensitizer were utilized. Owing to relatively deeper redox energy level for cobalt based electrolytes as compared to I₃^-/I^- redox system, possibility of obtaining high open-circuit voltage was explored. Employing a thin film of Ti on the metal mesh as the charge recombination blocking layer resulted in enhanced photoconversion efficiency. TCO-less DSSC in combination with cobalt electrolyte gave the power conversion efficiency of 4.89% under simulated solar irradiation.