The effects of iodine species on the performance of Gallium Di-Corrole (2-10-B1) dye in dye-sensitized solar cells have been investigated by density functional theory calculations. Calculations show that there are strong interactions between iodine (I-, I-2(-) or I-3(-)) and 2-10-B1 dye, but weak interaction between iodine molecule (I-2) and the dye. For these iodine ions, the most stable adsorption site of 2-10-B1 dye is the center metal Ga. When an iodine ion is adsorbed on Ga atom of 2-10-B1 dye, the charge of the dye is better separated. Moreover, partial negative charge of iodine ion is transferred to the dye to facilitate the dye regeneration. And the absorption spectrum of the dye is broadened and red-shifted. (C) 2015 Elsevier B.V. All rights reserved.