We have studied the influence of electrolytes on the photovoltaic performance of mercurochrome-sensitized nanocrystalline TiO 2 solar cells using LiI, LiBr, and tetraalkylammonium iodides as the electrolyte. Short-circuit photocurrent density (J s c ) and open-circuit photovoltage (V o c ) depended strongly on the electrolyte. J s c of 3.42mAcm - 2 and V o c of 0.52V were obtained for the LiI electrolyte and J s c of 2.10mAcm - 2 and V o c of 0.86V were obtained for the Pr 4 NI electrolyte. This difference in photovoltaic performance was due to the change in the conduction band level of the TiO 2 electrode. Large V o c of 0.99V was obtained for the LiBr electrolyte due to the large energy gap between the conduction band level of TiO 2 and the Br/Br 2 redox potential. Solar cell performance also depended strongly on organic solvent, suggesting that the physical properties of solvents such as Li ion conductivity and donor number affect photovoltaic performance.