High efficiency quasi-solid-state dye-sensitized solar cell based on polyvinyidene fluoride-co-hexafluoro propylene containing propylene carbonate and acetonitrile as plasticizers

Quasi-solid-state dye-sensitized solar cells (DSSCs) with different weight ratios of polyvinyidene fluoride-co-hexafluoro propylene (PVDF-HFP) containing two different plasticizers such as propylene carbonate (PC) and acetonitrile (AN) were fabricated and the effects of TiO₂ morphology, light intensities as well as different organic iodides on the solar cell performance were studied. Two TiO₂ photoelectrodes were designed by the coating of low (P1) and high molecular weight poly(ethylene glycol) (P2) incorporated into the TiO₂ suspension. The DSSCs fabricated with the P2 TiO₂ electrode show better performance in terms of short-circuit current densities (J_SC) and conversion efficiencies than the P1 for all the weight percentages of PVDF-HFP containing both plasticizers. Further, the maximum current density (J_SC) and conversion efficiency of PVDF-HFP containing different organic iodides follow the order: TBAI > TPAI > NH₄I irrespective of the solvents and light intensity. A good conversion efficiency of 6.74% with J_SC of 16.04 mA/cm², an open-circuit voltage (V_OC) of 0.657 V and a fill factor of 0.64 under illumination of 100 mW/cm² was obtained for the DSSC with 10% of PVDF-HFP containing 0.4 M of TBAI and 0.04 M of I₂ in PVDF-HFP/AN system.