Efficient, stable dye-sensitized solar cell using ionic liquid–solid polymer electrolyte

It is imperative to develop high-efficiency polymer electrolytes to advance energy storage technologies. The goal of this research is to use the exceptional properties of ionic liquids such as their superior ionic conductivity, thermal stability, and adjustable physical and chemical characteristics to improve polymer electrolytes through doping. This study explores the incorporation of ionic liquids into polymer matrices to create novel ionic-liquid-doped polymer electrolytes (ILDPEs). We synthesized a ILDPEs using Poly(ethyl methacrylate) (PEMA) as the host polymer with salt sodium iodide (NaI) doped with a new ionic liquid (1-hexyl-3-methylimidazolium iodide) synthesized using solution cast technique. Impedance spectroscopy revealed that doping ionic liquid enhances the ionic conductivity of the PEMA + NaI complex. Ionic conductivity significantly increased upon the addition of the ionic liquid (IL), reaching a maximum value of 7.7 × 10^–4 S/cm at room temperature. The ionic transference number (t_ion) for the polymer electrolyte with the highest ionic conductivity was calculated using Wagner polarization method while electrochemical stability window was calculated by linear Sweep Voltammetry. The crystalline nature of the ILDPEs films was studied using Polarizing Optical Microscopy (POM). To confirm the complex formation and bonding structure, Fourier-transform infrared spectroscopy (FTIR) and X-Ray Diffraction (XRD) were also employed. Finally, dye-synthesized solar cell (DSSC) and electric double-layer capacitor (EDLC) were fabricated using the highest ionic conducting polymer electrolytes.