Conductivity behaviour in novel quasi-solid-state electrolyte based on polyacrylonitrile and tetrahexylammonium iodide intended for dye sensitized solar cells

Abstract

The conduction of iodide ions in gel polymer electrolytes and the performance of dye sensitized solar cells containing such an electrolyte can be enhanced by incorporating a salt having a bulky cation. In this work, polyacrylonitrile (PAN) and Hex4N+Ī based gel electrolytes with ethylene carbonate and propylene carbonate as plasticizers have been studied. The variation of conductivity and molar conductivity with salt concentration has been discussed in order to understand the mechanism of iodide ion conductivity in this system. Out of the various compositions studied, the electrolyte containing 120 % salt with respect to weight of PAN showed the highest conductivity, 2.0 × 10-3 Scm-1 at 25 °C and a glass transition at - 102.3 °C. The electrolytes exhibit predominantly ionic behaviour and because of the bulky cation a negligible cationic transport is shown. A quasi-solid-state dye sensitized solar cell was fabricated employing the optimized gel electrolyte. This cell showed an energy conversion effciency of 3.1% and a short circuit current density of 8.1 mAcm-2 under irradiation of 1000 Wm-2.