Influence of I₂ concentration and cations on the performance of quasi-solid-state dye-sensitized solar cells with thermosetting polymer gel electrolyte

Thermosetting polymer gel electrolytes (TPGEs) based on poly(acrylic acid)-poly(ethylene glycol) (PAA-PEG) hybrid were prepared and applied to fabricate dye-sensitized solar cells (DSCs). N-methylpyrrolidone (NMP) and γ-butyrolactone (GBL) were used as solvents for liquid electrolytes and LiI and KI as iodide source, separately. The microstructure of PAA-PEG shows a well swelling ability in liquid electrolyte and excellent stability of the swollen hybrid. The TPGE was optimized in terms of the liquid electrolyte absorbency and ionic conductivity photovoltaic performance. Quasi-solid-state DSCs containing TPGE with optimized KI electrolyte show higher efficiency, voltage, fill factor, and lower photocurrent than those with LiI electrolyte. The related mechanism was discussed. A quasi-solid-state DSC fabricated with optimized polymer gel electrolyte obtained an overall energy conversion efficiency of 4.90% under irradiation of 100 mW/cm² (AM1.5).