Ionic conductivity improvement in poly (propylene) carbonate-based gel polymer electrolytes using 1-butyl-3-methylimidazolium iodide (BmimI) ionic liquid for dye-sensitized solar cell application

Gel polymer electrolytes (GPEs) are prepared by mixing poly (propylene) carbonate (PPC) with various weight percentages of 1-butyl-3-methylimidazolium iodide (BmimI) ionic liquid. The GPEs consist of PPC host polymer, NaI iodide salt, ethylene carbonate (EC), propylene carbonate (PC), BmimI ionic liquid, and iodine (I2). The optimum BmimI ionic liquid content was found to be 60 wt% with respect to the wt% of PPC polymer with the highest ionic conductivity of 4.79 × 10−3 S cm−1. Temperature-dependent ionic conductivity studies exhibited that gel polymer electrolytes obey Arrhenius thermal-activated model. X-ray diffraction (XRD) study confirms the complexation between host polymer (PPC polymer), sodium iodide salt, and BmimI ionic liquid. Dye-sensitized solar cells are fabricated and GPEs are sandwiched between the working and counter electrodes and tested under the one Sun illumination. The highest energy conversion efficiency of 6.14% is achieved with the addition of 60 wt% of BmimI.