Preparation of an Au nanoparticle-graphene oxide quantum dot hybrid and its use in surface-enhanced Raman scattering

An Au nanoparticle-graphene oxide quantum dot hybrid was prepared by the in-situ chemical reduction of HAuCl₄ in an aqueous solution containing HAuCl₄ and graphene oxide quantum dots using sodium citrate as a reducing agent under reflux for 1 h, followed by repeated centrifugation for three times at 15 000 r/min for 10 min. The hybrid was characterized by SEM, TEM, EDS, UV spectroscopy, XPS and Raman spectroscopy. Results indicated that the I_G/I_D value of the hybrid was higher than that of graphene oxide quantum dots, indicating that the number of defects was decreased after the reduction. When the hybrid was used in surface enhanced Raman scattering (SERS) to detect rhodamine 6G, the SERS intensity of the hybrid substrate was 9 times that of a substrate of Au nanoparticles prepared under the same procedure and conditions without adding graphene oxide quantum dots and 12 times that of a graphene oxide quantum dot substrate, indicating that the hybrid has possible use in SERS detection.