Fabrication and efficiency enhancement of water-based dye-sensitized solar cells by interfacial activation of TiO2 mesopores

Abstract

Dye-sensitized solar cells were fabricated by using water-based electrolytes for the purpose to realize environmentally benign, green solar cells in which electrolyte solvent, water, can serve as a recyclable medium. Mesoporous TiO2 electrode was treated with ozone and UV light for hydrophilic conversion of the TiO2 mesopore and was dye-sensitized with Ru(bipy)2 (SCN)2 in the presence of 4-tert-butylpyridine. These processes for surface activation highly improved photocurrent density and voltage of the electrode in contact with aqueous electrolytes that contain iodide/iodine as redox agents. Replacement of a portion of water with ethanol in the electrolyte composition further enhanced photovoltaic performance. With aqueous electrolyte containing 35% ethanol, photocell achieved power conversion efficiency of 2.2% under exposure to simulated solar light of 100 mW/cm2.