Polyethylene glycol (PEG) and trimethylol propane triacrylate (TMPTA) were used as photo-crosslinkable polymer electrolytes for dye-sensitized solar cells (DSSCs). PEG and trifunctional TMPTA formed a crosslinked structure upon light illumination, as confirmed by the solubility test and FHR spectroscopy. In order to make close contact with the TiO2 porous film, the polymeric electrolyte was prepared by photo-polymerization after injecting the monomer electrolyte solution into the porous film. The cross-sectional FE-SEM images showed the penetration of the electrolyte into the porous TiO2 layer. Under AM 1.5 (100 mW/cm(2)) light irradiation for up to 30 min, a maximum 21% increase in the photo-conversion efficiency(eta%) was observed. The electrolyte containing PEG and 20 wt% TMPTA showed a maximum increase in the photo-conversion efficiency from 2.75% to 3.35% with 30 min of light illumination. Also, the DSSCs with the novel crosslinkable PEG/TMPTA based polymer electrolyte showed improved long-term stability in comparison to those with electrolytes containing only PEG. (c) 2009 Elsevier Ltd. All rights reserved.