Preparation and optic properties of water-soluble ZnO quantum dots

SiO2/ZnO water-soluble quantum dots were prepared by modification of (3-mercaptopropyl) tri-ethoxysilicane. The emission spectral peak of exciton fluorescence was raised by about 4 times in comparison with that of the quantum dots obtained by direct SiO2 deposit on ZnO without modification. The introduction of hydrosulfide group(HS - ) on ZnO, renders the quantum dots good water solubility, unique fluorescent stability and anti-congregation even at higher NaCl concentration. The water soluble blue SiO2/ZnO quantum dots were also prepared by this method with some modification of the reaction conditions. The photogenic wavelength of this blue quantum dots was found to be 420 nm. The emission spectra were very symmetrical without obvious red tall. The full widths half maximum were only 46 nm.