Design and Fabrication of Long-Term Stable Dye-Sensitized Solar Cells: Effect of Water Contents in Electrolytes on the Performance

The effects of water-containing I−/I3− liquid electrolytes on the photovoltaic performance and long-term stability of ruthenium based complex Z907 dye was examined in dye-sensitized solar cells (DSSCs). Despite of high water content up to 60 vol% in organic solvent-based liquid electrolyte, the photovoltaic properties and long-term stability measured under the standard global (G) air-mass (AM) 1.5 solar irradiation were not significantly affected. The underlying correlation between the effects of water and the photovoltaic performances were identified by UV–visible spectroscopy and electrochemical impedance spectroscopy. We investigated the long-term stability of performance for DSSCs in conjunction with I−/I3− redox electrolytes in different water compositions. The findings revealed that the competitive photovoltaic performance and long-term stability of water-containing DSSCs mainly depends on the hydrophobicity of dye as well as the transport phenomena of I3− throughout the electrolytes. The water-based DSSCs proposed herein are free from water permeation issues and these results will provide great insight into the development of less expensive and more environmental friendly DSSCs.