Multichannel detection x-ray absorption near edge structures study on the structural characteristics of dendrimer-stabilized CdS quantum dots

Starburst poly-(amidoamine) dendrimers were used to obtain dendrimer stabilized CdS nanoparticles, or quantum dots (QDs). The average particle size of the QDs was examined by UV-vis absorption spectra and powder x-ray diffraction measurements. The technique of x-ray absorption near edge structure (XANES) near the S K-edge was employed to study the structural characteristics of a series of QDs. The use of a multichannel detection scheme in XANES, monitoring total electron yield, x-ray fluorescence yield, and photoluminescence yield simultaneously, was demonstrated to be a powerful tool to evaluate the structure of the QDs from a sulfur perspective. The relationship between the luminescence property and the local structure of sulfur in the QDs was also discussed on the basis of the results of x-ray excited optical luminescence and XANES studies.