Preparation And Modification Of Zno Quantum Dots

Semiconductor quantum dots (Quantum dots, also known as QDs), their size are usually 1~10nm, which are same as the diameter of biological macromolecules (proteins). Due to their unique optical properties, such as the wide excitation range, narrow emission peak, tunable emission wavelength and photostability, the quantum dots have been used in the field of life science research as a new kind of fluorescent probe. At present, these quantum dots which are applied to bio-medicine field are almost the CdTe and CdSe, where the toxic elements of Cd to make their application limited. However, the ZnO quantum dots have excellent fluorescent properties, cheap materials and not contain toxic elements. But the water-dispersible ZnO quantum dots what meet the biological testing requirements is still rarely reported. Therefore, some works and innovative results have been done, and the main research contents are as follows:(1) In this paper, ZnO quantum dots with a strong visible emission were synthesized in ethanol using a sol-gel method. By the control of different reaction conditions, the fluorescence emission wavelength of ZnO quantum dots can be precise regulated successfully. (2) In this paper, ZnO quantum dots were coated with silane by using 3-aminopropyl-triethoxysilane (APTES), and prepared the ZnO/Aminopropyl -siloxane quantum dots with a core-shell structure. The fluorescence intensity of these core-shell quantum dots is one time higher than ZnO quantum dots'. Besides, these core-shell quantum dots also have a good stability, and are able to maintain excellent fluorescent properties in the aqueous phase. (3) Based on ZnO/Aminopropyl-siloxane quantum dots, polyethylene glycol (PEG-600) was used for surface modification, with this method, the ZnO/Aminopropylsiloxane-PEG quantum dots (ZnO-ASP quantum dots) were synthesized which could be dispersed in the water stably. (4) Through the application of the water-dispersible ZnO-ASP quantum dot on the onion cells imaging and the effect of Arabidopsis thaliana growth-stimulating experiments, confirming these ZnO-ASP quantum dots have a high bio-availability.