A Novel Poly(acrylonitrile)-Based Quasi-Solid-State Electrolyte for Dye-Sensitized Solar Cells

Abstract

The use of volatile liquid electrolytes limits the practical application of dye-sensitized solar cells (DSSCs) because of stability issues. Gel-type electrolytes have shown promising results in terms of cell stability and efficiency. Poly(acrylonitrile) has been known for its high ion solvation ability and structural stability.1 Herein, we report a quasi-solid-state DSSCs (QS-DSSCs) using gel polymer electrolyte (GPE) based on poly( acrylonitrile-co-methyl acrylate) (i.e. P(AN-co-MA)) dissolving a iodide-acetonitrile solution. The MA group rotates freely on the polymer chain to effectively coordinate the electrolyte solution into the polymer matrix.2By adjusting the polymer content, we can control the gelation time of the GPE for smooth electrolyte injection into the cells. No filler is needed to expedite the gelation process. The QS-DSSCs exhibit higher short-circuit currents than liquid-state DSSCs (L-DSSCs). The polymer chains may have adhered to the TiO2films in the QS-DSSCs to suppress charge leakage and promote the photocurrent. However, the QS-DSSCs have smaller fill factors than the L-DSSCs, likely due to lower ionic conductivity of the GPE relative to the liquid electrolyte. Using the N719 dye as the sensitizer, the QS-DSSCs have a power conversion efficiency of 9.5 % whereas the L-DSSCs show a similar efficiency of 9.6 %. Importantly, the proposed QS-DSSCs presented considerable improvements in long-term stability when subjected to accelerated aging. This developed GPE has presented a promising potential to replace liquid-state electrolytes used in DSSCs.