Long-term stable dye-sensitized solar cells based on UV photo-crosslinkable poly(ethylene glycol) and poly(ethylene glycol) diacrylate based electrolytes

UV photo-crosslinkable polymer electrolytes based on poly(ethylene glycol) (PEG) and poly(ethylene glycol) diacrylate (PEGDA) were used in dye-sensitized solar cells (DSSCs). PEG and bifunctional PEGDA formed a crosslinked structure upon UV light illumination, confirmed by the solubility test and FTIR spectroscopy. The polymeric electrolyte was prepared by photo-polymerization after injecting the monomer electrolyte solution into the porous film in order to make close contact with the TiO2 porous film. Under AM 1.5 (100 mW/cm2) light irradiation for up to 20 min, a maximum 62% increase in the photo-conversion efficiency (η%) was observed. The DSSCs with the crosslinkable PEG/PEGDA based polymer electrolyte showed improved long-term stability in comparison to those with electrolytes containing only PEG. Also, the effects of solvent on stability of the DSSCs were investigated.