Two-Phase Route to High Quality ZnO Quantum Dots with High Stability of Dispersity, Structure and Optical Properties

A two-phase system methanol-hexane is developed in the current work. These colloidal ZnO quantum dots (QDs) emission with yellow prepared by a traditional sol–gel approach can realize surface modification with oleic acid (OA) via the two-phase route. The Pearson's Hard and Soft [Lewis] Acid and Base Principle together with the effect of microemulsion determines the OA capping on ZnO QDs. These ZnO QDs after surface modification with OA are highly stable in structure and optical properties as well as dispersity. This two-phase route successfully inhibits ZnO QDs from turning to acetate anion intercalated Zn based hydroxyl double salts. The visible emission intensity of these ZnO QDs after surface modification is unchanged as time went on. The dispersity of these ZnO QDs after surface modification is improved greatly and these ZnO QDs after surface modification can be stable in non-polar solvents for a long time.