Synthesis and photoluminescent properties of CdS/SiO2 nanorod core-shell structure

Core/shell structures of CdS/SiO2 were synthesized through the ammonium hydroxide catalyzed hydrolysis of tetraethylorthosilicate (TEOS) in alcohol media containing pre-synthesized CdS nanorods. X-ray diffraction(XRD), transmission electron microscopy (TEM), UV-Vis spectroscopy and photoluminescence spectroscopy were employed to characterize the obtained core-shell structures. The thickness of the amorphous SiO2 shell ranges from 10 to 30 nm, and increases with the concentration of the TEOS used. The photoluminescence intensity of the core-shell structures is enhanced for the CdS nanorod samples with only a thin layer (< 10 nm) of SiO2 shell on the CdS nanorod, and is reduced for the sample with a thicker SiO2 shell. Possible reasons contributing to the variations of the photoluminescence were discussed.