A novel gel electrolyte was prepared by dispersing the polymer-grafted ZnO nanoparticle into liquid electrolyte. This gel electrolyte behaves long-term stability as the poly(ethylene glycol methyl ether) molecules are strongly connected to ZnO nanoparticles with covalent bond in polymer-grafted ZnO nanoparticle. A quasi-solid-state dye-sensitized solar cell (DSC) based on this gel electrolyte yields the energy transfer efficiency of 3.1% at AM 1.5 direct irradiation of 75 mW cm(-2) light intensity. Addition of 4-tert-butylpyridine into the electrolyte results in dramatically improved short circuit current density I-sc, and the overall efficiency is also improved to 5.0%, while the open circuit voltage (V-oc) and fill factor (ff) are insensitive to the presence of 4-tert-butylpyridine. DSC fabricated with this novel gel electrolyte displays better thermal stability than those solidified with the conventional nanoparticle ZnO(Ac). (c) 2006 Elsevier B.V. All rights reserved.