Preparation of ZnSe/ZnS Core-Shell Quantum Dots Under UV Irradiation
ZHANG Cong-cong1, LIU Lian-dong2, XIA Lei1, LI Xue3, ZHANG Xiao-kai1*
1. School of Physics and Electronics, Shandong Normal University, Ji’nan 250014, China
2. School of Chemical Engineering and Materials Science, Shandong Normal University, Ji’nan 250014, China
3. School of Chemical Engineering and Materials Science，University of Ji’nan, Ji’nan 250022, China
Abstract：In order to improve the traditional water phase method，ZnSe/ZnS core-shell quantum dots were synthesized at room temperature by ultraviolet irradiation method, which is more safe, simple, economical and environmentally friendly. The optimal growth and modification conditions for the core-shell structure of ZnSe/ZnS QDs were optimized by adjusting the experimental conditions such as pH value, illumination time and reactant ratio, so that it has good dispersion, time stability and luminescent properties. Ultraviolet irradiation can stimulate free electrons to trigger chemical reactions. In this study, thioglycolic acid (TGA) and glutathione (GSH) were used as both stabilizers and dispersants to control the growth of QDs and obtain evenly dispersed QDs. The introduced photosensitive material is also the S source to form ZnS. The crystal structure and optical properties of QDs were characterized by X-ray diffraction (XRD), electron microscopy (EM), Energy Dispersive X-ray spectroscopy (EDX), photoluminescence spectroscopy (PL) and UV-Vis. The results show that GSH-modified QDs have better stability and fewer surface defects than TGA-modified QDs. ZnS shell growth can effectively improve this defect, but the over-thick shell will lead to a risk of quenching the intrinsic radiation. This experiment explored this preparation method in-depth, and for the first time，various influencing factors and synthetic conditions were supplemented. Based on the analysis of the theory and the experiment results, the optimal synthesis conditions of ZnSe/ZnS core-shell quantum dots are obtained.
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