The net enhancement of open-circuit voltage (V-oc) of dye-sensitized solar cells (DSSCs) was achieved with the novel electrolyte composed of interhalogen based binary-redox couples without regard to the choice of sensitizers. The interhalogen ion, I2Br-, was formed in the conventional iodine-based electrolyte by both chemically and electrochemically and it was found to produce an extra redox pair, (I-, Br-)/I2Br-, with new energy state at a more positive potential than that of I-/I-3(-). The Fermi level of the electrolyte shifted positively by the weighted-average of the two redox systems. It induced the increase of V-oc up to 30, 60, and 50 mV for cis-diisothiocyanato-bis(2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium(II) bis(tetrabutylammonium) (N719), cis-dicyano-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid) ruthenium(II) (Ruthenizer 505 or Ru505), and 2',4',5',7'-tetrabromofluorescein (eosin Y) dyes, respectively, without affecting the short circuit current much. It corresponded to the enhancement of the overall power conversion efficiency (eta) up to 8, 14, and 13%, respectively. Moreover, the degree of enhancement of V-oc, was controllable by varying [I2Br-] since the higher the contribution of [I2Br-] the more positive shift in the energy level of the binary redox couples. (C) 2013 Elsevier Ltd. All rights reserved.