Influence of organic additive to PVDF-HFP mixed iodide electrolytes on the photovoltaic performance of dye-sensitized solar cells

The influence of 5-amino-1,3,4-thiadiazole-2-thiol (ATDT) on the ionic conductivity of poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP) polymer electrolytes with mixed iodide salts (potassium iodide (KI) and tetrabutylammonium iodide (TBAI)) and iodine (I 2 ) were studied for dye-sensitized solar cells (DSSCs). The pure and different weight percentage (wt%) ratios (2%, 3%, 4%, 5% and 6%) of ATDT modified PVDF-HFP/KI+TBAI/I 2 electrolyte films were prepared by solution casting technique using DMF as a solvent. The polymer electrolyte films were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD), electrochemical impedance spectroscopy and scanning electron microscopy (SEM). The pure PVDF-HFP/TBAI+KI/I 2 electrolyte exhibited the ionic conductivity value of 9.99×10 −6 S cm −1 at room temperature, which was found to be improved to a maximum value of 2.82×10 −4 S cm −1 at 4 wt% of ATDT modified polymer electrolyte. The photovoltaic characterization studies showed higher power conversion efficiency of 4.64% for DSSC assembled with the optimized wt% of ATDT modified polymer electrolyte than the pure PVDF-HFP/KI+TBAI/I 2 electrolyte (1.88%) at an illumination intensity of 60 mW/cm 2 . Hence, the studies concluded that the ATDT modified polymer electrolyte can be a suitable material for DSSC applications.