Synthesis and Characterization of L-cysteine-modified ZnSe:Co/ZnSe Quantum Dots

In this paper, ZnSe:Co/ZnSe QDs were synthesized by co-precipitation technique in aqueous phase using L-cysteine as modifier, the experimental results were characterized by X-ray power diffraction(XRD), transmission electron microscope(TEM), infrared spectrum(IR)and photoluminescence spectrum(PL). The results showed that the ZnSe:Co/ZnSe QDs was spherical with diameter around 3.2nm, belonged to cubic sphalerite structure and had good fluorescent characteristics. The photoluminescence emission intensity of the L-cysteine modified ZnSe:Co/ZnSe core/shell QDs was enhanced by doping Co2+ and coating ZnSe shell to the core ZnSe. After doped with Co2+ and coated with ZnSe shell, the fluorescence quantum yields of the as-prepared ZnSe:Co/ZnSe QDs increased from 4.93% to 29.94%. The L-cysteine modified on the surface of ZnSe:Co/ZnSe renders the QDs water-soluble and biocompatible.