The exfoliated montmorillonite (exMMT) nanoplatelets that carry negative charges are capable of adsorbing 1-methyl-3-propyl-imidazolium cations to form a gel-type ionic liquid-based electrolyte system for dye-sensitized solar cell (DSSC). Interestingly, it also increases the power conversion efficiency of DSSC from 6.58% to 7.77% at full sun. The increased efficiency is attributed to the decreased resistance of gel electrolyte system and enhanced reduction reaction rate at the counter electrode, both of which are related to the two-dimensional electrolyte nature of exMMTs that repel the I(-)/I(3)(-) redox couples toward their major conduction pathway. (C) 2011 Elsevier Inc. All rights reserved.