Water-soluble ZnO fluorescent quantum dots

Water-soluble ZnO fluorescent quantum dots (QDs) with strong visible emission were synthesized via reverse emulsion process using zinc nitrate, diethanolamine (DEA) and modification molecules of oleic acid (OA) as staring materials. The surface species of (2HOR')(z)ZnO(ON)(x-y)[OOC-R](y) on ZnO QDs due to chemical reaction between ZnO nanoparticles and OA molecules constitutes interface states, which is the origin of strong and tunable visible light due to. the radiative recombination of surface species into ground state. The moiety hydroxyl groups on the surface of ZnO originated from DEA endow the water-soluble features of ZnO QDs. Surface passivated ZnO QDs can be considered as new generation of luminescent probe.