Influence of Molecular Weight of PEO on Performance of Quasi-solid-state Dye-sensitized Solar Cells

Quasi-solid-state dye-sensitized solar cells (DSCs) were prepared using gel electrolyte gelated by poly(ethylene-oxide) (PEO) with different molecular weight. With the increase in PEO molecular weight, the short circuit current densities (Jsc) increase significantly, which is related to the increase in I - diffusion due to the increase in free volume of gel electrolyte. However, only a slight increase in open voltage (Voc) is observed, which is explained by the decrease in dark current arising from the reduction of triiodide (I3-) by conduction band electrons.