Membrane-based electrolyte sheets for facile fabrication of flexible dye-sensitized solar cells

Highlights: → A new electrolyte sheet was developed for flexible dye-sensitized solar cells (DSCs). → It is composed of a porous polyethylene membranes and ionic liquid electrolytes. → The electrochemical properties of the electrolyte sheets were evaluated. → High-performance flexible DSCs with the electrolyte sheets were facilely fabricated. - Abstract: New electrolyte sheets based on porous polyethylene membranes for flexible dye-sensitized solar cells have been developed. Ionic liquid electrolytes are accommodated in commercial polyethylene membranes to form the electrolyte sheets. The morphology of membranes and iodine concentrations in ionic liquid are varied. The electrochemical measurement results show that the morphology, pore structure, and iodine concentration affect mass transport in electrolyte sheet, as well as charge transfer between platinum electrode and electrolyte sheet greatly. Based on these electrolyte sheets, lamination method instead of conventional vacuum injection of electrolyte is used to fabricate flexible dye-sensitized solar cells. Optimal device with an open-circuit voltage (Voc) of 0.63 V, a fill factor of 0.58, and a short-circuit current density (Jsc) of 6.17 mA cm-2 at an incident light intensity of 100 mW cm-2 is obtained, which yields a light-to-electricity conversion efficiency of 2.25%.