Preparation of High Transmittance Platinum Counter Electrode at an Ambient Temperature for Flexible Dye-Sensitized Solar Cells

High transmittance Pt nanoparticles are prepared on indium tin oxide/polyethylene-naphthalate) (ITO/PEN) substrate at an ambient temperature of 40 0C and employed as counter electrode (CE) for dye sensitized solar cells (DSSCs). The deposited nano-Pt materials are characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Symmetrical cell fabricated with CE containing 1.8 wt% nano-Pt shows high exchange current density and low charge transfer resistance, as confirmed by Tafel polarization and electrochemical impedance spectroscopy (EIS) respectively. The Ti foil sub-module DSSC (10 cm × 10 cm) having such CE exhibits a high conversion efficiency of 7.47% at an illumination of 100 mW/cm2. Further, the DSSC maintains >90% of the baseline efficiency after being exposed for more than 2000 hrs in continuous one sun light soaking at 60 °C.