Improvement of the optical and photocatalytic properties of ZnSe QDs by growth of ZnS shell using a new approach

In this work ZnSe and ZnSe/ZnS QDs were synthesized via a rapid, room temperature photochemical approach. Zn(Ac)2, Na2SeO3 and TGA were used as precursors. As an UV-sensitive material, TGA acted simultaneously both as the capping agent and S2− source for ZnS shell growth. Crystal structures and optical properties of the QDs were characterized by means of X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Field emission scanning electron microscope (FESEM), Photoluminescence spectroscopy (PL), Energy dispersive X-ray analysis (EDAX), UV-Visible (UV-Vis) spectroscopy. Band-gap of the ZnSe QDs was obtained about 3.45 eV. PL spectra deconvolution obtained three peaks which are related to the emission of band edge, surface states and deep levels. After ZnS shell growth, surface trap states emission was quenched significantly and band edge emission was increased considerably. ZnSe QDs indicated a good activity for Methylene Orange)MO( photo-degradation that it was improved after ZnS shell growth significantly.