The performance of dye sensitized nanocrystalline TiO₂ solar cells based on quasi-solid state PAN electrolytes containing a series of six quaternary ammonium iodide salts NH₄I, Eth₄NI, Prop₄NI, But₄NI, Pent₄NI, Hex₄NI with different cation sizes has been evaluated. Even though the total ionic conductivity decreases with increasing cation size from NH₄I to Hex₄NI, the iodide ion conductivity in the electrolytes increases with cation size. The open circuit photovoltage (V_oc) of the dye sensitized solar cells also increases with cation radius. The efficiency of the DSSCs varies with cation size and exhibits a maximum for Prop₄NI salt. The short circuit photo current density (J_sc) follows a similar variation with cation size, suggesting a strong correlation between the cation size dependence of efficiency and J_sc. The DSSC fabricated with tetrapropylammonium iodide exhibited the maximum efficiency of 4.30% with maximum J_sc of 10.78 mA cm⁻² and a V_oc of 0.746 V. The results have been interpreted on the basis of “the electrolyte effects” where J_sc is determined essentially by the iodide ion conductivity and “the electrode effects” where the J_sc and V_oc are determined by the cation adsorption in the dyed TiO₂ electrode and resulting electron dynamics at the semiconductor/electrolyte interface. For DSSCs with small cations, electrolyte effects appear to be dominating and rate determining while for DSSCs with larger cations, electrode effects appear to be dominating and rate determining.