Enhanced performance of 4,4′-bipyridine-doped PVDF/KI/I2 based solid state polymer electrolyte for dye-sensitized solar cell applications

Abstract

Pure (PVDF/KI/I2) and 4,4′-bipyridine-doped PVDF/KI/I2 solid state polymer electrolytes were prepared by solution casting method using N,N-dimethylformamide (DMF) as solvent. The solid state polymer electrolytes were characterized by the powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR), AC-impedance, dielectric measurements and scanning electron microscopy (SEM) analysis. The crystallinity of the solid state polymer electrolytes was analyzed by PXRD measurement. The functional groups of the solid state polymer electrolytes were confirmed by FTIR analysis. The AC-impedance analysis was carried out to calculate the ionic conductivity of the solid state polymer electrolytes. The ionic conductivity value of pure (PVDF/KI/I2) and 4,4′-bipyridine-doped PVDF/KI/I2 solid state polymer electrolytes are 2.00 × 10−6 S cm−1 and 4.60 × 10−5 S cm−1, respectively. The dielectric properties of solid state polymer electrolytes were calculated by using the dielectric measurements. From the SEM analysis, the surface morphology of the solid state polymer electrolytes was analyzed. The power conversion efficiencies of pure (PVDF/KI/I2) and 4,4′-bipyridine-doped PVDF/KI/I2 solid state polymer electrolytes are 1.8% and 4.4%, respectively. 4,4′-bipyridine-doped PVDF/KI/I2 solid state polymer electrolyte has higher power conversion efficiency due to its increased amorphous nature and ionic mobility.