Synthesis and fluorescence properties of CdSe/CdS nanoparticles in aqueous media

On the basis of unique structural characteristics of alpha-cyclodextrin, alpha-cyclodextrin modified CdSe/CdS nanoparticles have been successfully synthesized in aqueous media. Techniques of AFM, TEM, EDS, FTIR, UV-vis absorbance and photoluminescence spectra were used to characterize the morphology, composition and optical characteristics of the synthesized nanoparticles. The results showed that the as-synthesized nanoparticles were elliptical and composed of several small particles. Their average length and diameter were about 20 nm and 15 nm. CdSe/CdS nanoparticles had single well-crystallized hexagonal structure. Packaged with a shell of CdS on the surface, alpha-CD/CdSe-CdS nanoparticles exhibited a red shift in the absorption spectrum, intensity growth in the emission spectrum and a substantial increase in Quantum yields. The size distribution could be adjusted by precursor ratios in the presence of alpha-cyclodextrins.