Effects of compositions on properties of PEO–KI–I2 salts polymer electrolytes for DSSC

The effects of compositions on properties of PEO/KI/I2 salts polymer electrolytes were investigated to optimize the photovoltaic performance of solid state DSSCs. XRD pattern for the mole ratio 12:1 of [EO:KI] was showed the formation of complete amorphous complex. DSC results also confirmed the amorphous nature of the polymer electrolyte. The highest value of ionic conductivity is 8.36 × 10− 5 S/cm at 303 K (ambient temperature) and 2.32 × 10− 4 S/cm at 333 K (moderate temperature) for the mole ratio 12:1 of EO:KI complex. The effect of contribution of [I−] and [I3−] concentration with conductivity were also evaluated. FTIR spectrum reveals that the alkali metal cations were co-ordinated to ether oxygen of PEO. The formation of polyiodide ions, such as symmetric I3− (114 cm− 1) and I5− (145 cm− 1) caused by the addition of iodine was confirmed by FT Raman spectroscopic measurements. The optimum composition of PEO–KI–I2 polymer electrolyte system for higher conductivity at ambient and moderate temperatures was reported. A linear Arrhenius type behaviour was observed for all the PEO–KI polymer complexes. Transport number measurements were carried out for several polymer electrolyte compositions. Dye-sensitized solar cells were fabricated by using higher conductivity polymer electrolyte compositions and its photoelectrochemical performance was investigated. The fill factor, short-circuit current, photovoltage and energy conversion efficiency of the DSSC assembled with optimized electrolyte composition were calculated to be 0.563, 6.124 mA/cm2, 593 mV and 2.044% respectively.