Improved long-term stability of dye-sensitized solar cell employing PMA/PVAc based gel polymer electrolyte

Abstract

Gel polymer electrolytes based on blends of poly(methyl acrylate) (PMA) and poly(vinyl acetate) (PVAc) were prepared using tetrapropylammonium iodide (TPAI) salt, 1-butyl-3-methylimidazolium iodide (BMII) ionic liquid and ethylene carbonate (EC) plasticizer. The mass fraction of EC, WEC was varied while the masses of the other components were kept constant in order to study the dependence of dye-sensitized solar cell (DSSC) performance on EC concentration. Incorporation of EC in PMA/PVAc-TPAI-BMII has enhanced the efficiency of the DSSC. The efficiency enhancement is due to the increase in short circuit current density, Jsc, arising from the conductivity enhancement brought about by the EC. A DSSC with TPAI-BMII-EC liquid electrolyte was fabricated and its photovoltaic and stability performance were investigated and compared with DSSC with PMA/PVAc-TPAI-BMII-EC gel electrolyte. PMA/PVAc decreases the Jsc from 27.87 to 22.91 mA cm−2 and efficiency, η from 12.28 to 9.67%. Linear sweep voltammetry studies reveal that PMA/PVAc decreases the ion motion in the electrolyte. Although PMA/PVAc deteriorates the performance of DSSC, but it improves the stability performance of DSSC by suppressing the recombination loss as evidenced from the increase in charge transfer resistance at the TiO2 electrode and longer electron recombination lifetime.