A new kind of 1-phenyl-3-methyl-4-octadecyl-5-pyrazolone (PMOP)-capped ZnO nanoparticle has been synthesized and characterized with UV-VIS, IR and fluorescent spectra. The material was used as a framework to form a quasi-solid-state electrolyte and employed in dye-sensitized solar cell (DSSC). Since the long alkyl-chain of PMOP interacts with liquid solvent, the quasi-solid-state DSSC with PMOP-capped nanoparticles shows higher stability in comparison with that of the liquid device and gives a comparable overall efficiency of 6.8% under AM 1.5 illumination.