Growth of Au nanocrystals on CdS nanorods

Abstract

Nanorods of S(2-) rich US were synthesized by a reaction of excess S versus Cd precursors in the presence of ethylene diamine. The photoluminescence (PL) emission from the S(2-) rich CdS nanorods was broad with a peak at similar to 710 nm, which was 40 nm longer in wavelength than the PL peak from Cd(2+) rich CdS (similar to 670 nm) nanorods. The influence of surface electron or hole trap states on the luminescent pathway of CdS nanorods will be discussed to explain these shifts in wavelength. Nanocrystals of Au similar to 2 nm in size were grown on S(2-) rich surfaces of CdS nanorods. Significant luminescence quenching was observed from the Au nanocrystals on the CdS nanorods due to interfacial charge separation. Charge separation by the Au nanocrystals on the CdS resulted in enhanced photocatalytic degradation of Procion red mix-5B (PRB) dye in an aqueous solution under UV light irradiation.