Effect of styrene–acrylonitrile content on 0.5 M NaI/0.05 M I2 liquid electrolyte encapsulation for dye-sensitized solar cells

Abstract

The effect of a gel polymer electrolyte (GPE) as the redox electrolyte used in dye-sensitized solar cells was studied. A GPE solution consisting of 0.5 M sodium iodide, 0.05 M iodine, and ethylene carbonate/propylene carbonate (1:1 w/w) binary solvents was mixed with increasing amounts of styrene-acrylonitrile (SAN). Bulk conductivity measurements show a decreasing trend from 4.54 to 0.83×10 −3 S cm −1 with increasing SAN content. The GPE exhibits Newtonian-like behavior and its viscosity increases from 0.041 to 1.093 Pa s with increasing SAN content. A balance between conductivity (1.3×10 −3 S cm −1 ) and viscosity (1.4 Pa s) is observed at 19 wt.% SAN. Fourier transform infrared spectroscopy detects elevated ring torsion at 706 cm −1 upon the addition of SAN into the liquid electrolyte. This indicates that SAN does not bond with the liquid electrolyte. Finally, the potential stability window of 19 wt.% SAN, which ranges from −1.68 to 1.38 V, proves its applicability in solar cells.