ZnO　QDs　were　successfully　synthesized　by　using　a　simple　synthetic　route.　The　synthesized　ZnO　QDs　have　different　shapes　with　highly　crystalline　nature　and　their　size　was　found　to　be　ca.　3-5　nm.　At　the　same　time,　a　series　of　modified　N719　dyes　were　obtained　via　ion-exchange　reactions　and　characterized　by　FTIR　and　HRMS　measurements.　When　the　modified　N719　dyes　were　used　as　a　sensitizer　for　ZnO　QDs-based　flexible　solar　cells,　the　photovoltaic　properties　were　enhanced　significantly.　A　highest　efficiency　of　2.94%　was　achieved;　this　might　be　attributed　to　the　fact　that　the　aggregate　of　Zn　2+/dye　on　the　surface　of　ZnO　QDs　can　be　suppressed　efficiently　owing　to　a　less　carboxylated　(COOH)　bipyridyl　ligand　in　the　modified　N719　dye,　inhibiting　the　formation　of　chelation　between　ZnO　QDs　and　dye.　©　The　Royal　Society　of　Chemistry.　2012.