Performance characteristics of guanine incorporated PVDF-HFP/PEO polymer blend electrolytes with binary iodide salts for dye-sensitized solar cells

In this work, we have investigated the influence of guanine as an organic dopant in dye-sensitized solar cell (DSSC) based on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) polymer blend electrolyte along with binary iodide salts (potassium iodide (KI) and tetrabutylammonium iodide (TBAI)) and iodine (I₂). The PVDF-HFP/KI + TBAI/I₂, PVDF-HFP/PEO/KI + TBAI/I₂ and guanine incorporated PVDF-HFP/PEO/KI + TBAI/I₂ electrolytes were prepared by solution casting technique using DMF as solvent. The PVDF-HFP/KI + TBAI/I₂ electrolyte showed an ionic conductivity value of 9.99 × 10⁻⁵ Scm⁻¹, whereas, it was found to be increased to 4.53 × 10⁻⁵ Scm⁻¹ when PEO was blended with PVDF-HFP/KI + TBAI/I₂ electrolyte. However, a maximum ionic conductivity value of 3.67 × 10⁻⁴ Scm⁻¹ was obtained for guanine incorporated PVDF-HFP/PEO/KI + TBAI/I₂ blend electrolyte. The photovoltaic properties of all these polymer electrolytes in DSSCs were characterized. As a consequence, the power conversion efficiency of the guanine incorporated PVDF-HFP/PEO/KI + TBAI/I₂ electrolyte based DSSC was significantly improved to 4.98% compared with PVDF-HFP/PEO/KI + TBAI/I₂ electrolyte based DSSC (2.46%). These results revealed that the guanine can be an effective organic dopant to enhance the performance of DSSCs.