Synthesis and Characterization of ZnSe and ZnSe/ZnS Quantum Dots for Potential Biomedical Application

Colloidal ZnSe quantum dots were synthesized by using cheap and low toxic zinc oxide (ZnO) in an organic solvent system of 1-hexadecylamine (HDA), lauric acid (LA) and tri-n-octylphosphine (TOP). The effects of HDA dosage and growth time on the microstructure and optical properties of ZnSe were studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), spectrofluorometers and ultraviolet spectrophotometer, respectively. The results showed that ZnSe quantum dots with the best range of the size evolution were obtained under the condition of injection at 300 degrees C and growth at 260 degrees C by choosing the optimal parameters of ZnO:HDA:LA = 1:2.1:5.2 and 1 mol/L TOPSe. Its size became larger and the emission peak shifted obviously to red with the increasing of growth time. Meanwhile, the obtained ZnSe was of the wurtzite structure and had good uniformity. The fluorescence emission intensity and photochemical stability of ZnSe capping with ZnS layer was improved apparently, and the obtained ZnSe/ZnS QDs also had the good uniformity and monodispersity.