Suppression of Charge Recombination in Dye-Sensitized Solar Cells Using the Plasma Treatment of Fluorine-Doped Tin Oxide Substrates

Abstract

This study presents a novel strategy for increasing the efficiency of dye-sensitized solar cells (DSCs) through modifying the surface of the fluorine-doped tin oxide (FTO) substrates using an atmospheric pressure plasma treatment. This strategy allows the suppression of charge recombination at the interface between the FTO substrate and electrolyte due to the formation of a thin, compact TiO2 blocking layer (BL) on the FTO surface without cracks and holes. Furthermore, the transmittance of the plasma-treated FTO/BL interface is higher than that of the pristine structure due to the compact morphology of the BL on the plasma-treated FTO. Thus, this strategy enables simultaneous improvement in light harvesting and photo-generated carrier collection. DSCs that use plasma-treated FTO substrates achieve higher efficiencies of 8.86% compared with the 8.04% of the reference device.