Growth of Au nanocrystals on CdS nanorods

Abstract

Nanorods of S2− rich CdS were synthesized by a reaction of excess S versus Cd precursors in the presence of ethylene diamine. The photoluminescence (PL) emission from the S2− rich CdS nanorods was broad with a peak at ∼710 nm, which was 40 nm longer in wavelength than the PL peak from Cd2+ rich CdS (∼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 ∼2 nm in size were grown on S2− rich surfaces of CdS nanorods. Significant luminescence quenching was observed from the Au nanocrystals on the CdS nanorods due to interfacial charge separation. Change 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.