Poly(n-isopropylacrylamide) (PNIPAAm) and its nanocomposite with exfoliated montmorillonite (MMT) were prepared by soap-free emulsion polymerization and individually applied to gel the electrolyte systems for the dye-sensitized solar cells (DSSCs). Each exfoliated MMT nanoplatelet had a thickness of similar to 1 nm, carried similar to 1.8 cation/nm(2), and acted like a two-dimensional electrolyte. The DSSC with the LiI/I-2/tertiary butylpyridine electrolyte system gelled by this polymer nanocomposite had higher short-circuit current density (J(sc)) compared to that gelled by the neat 2 PNIPAAm. The former has a J(sc) of 12.6 mA/cm(2) an open circuit voltage (V-oc) of 0.73 V, and a fill factor (FF) of 0.59, which harvested 5.4% electricity conversion efficiency 2 (eta) under AM 1.5 irradiation at 100 mW/cm(2), whereas the latter has J(sc) = 7.28 mA/ cm(2), V-oc, = 0.72 V, FF = 0.60, and eta = 3.17%. IPCE of the nanocomposite-gelled DSSC were also improved. Electrochemical impedance spectroscopy of the DSSCs revealed that the nanocomposite-gelled electrolytes significantly decreased the impedances in three major electric current paths of DSSCs, that is, the resistance of electrolytes and electric contacts, impedance across the electrolytes/dye-coated TiO2 interface, and Nernstian diffusion within the electrolytes. The results were also consistent with the increased molar conductivity of nanocomposite-gelled electrolytes. (c) 2007 Wiley Periodicals, Inc.