Facile synthesis of gold nanoparticles-graphene oxide films and their excellent surface-enhanced Raman scattering activity

We have demonstrated a green and facile approach to prepare the gold nanoparticles-graphene oxide (Au NPs-GO) film using the electrostatic self-assembly method. Cubic Au NPs with positive charge were firstly synthesized by a seed-growth method. By alternating deposition of the negatively charged GO sheets and Au NPs on the quartz substrate, the Au NPs-GO film can be achieved. AFM images show that GO sheets fully covered the quartz substrate after twice deposition. Meanwhile, Au NPs scattered on the surface of film can be found. The Au NPs-GO film exhibits the desirable surface-enhanced Raman scattering (SERS) properties against Rhodamine 6G molecules, including the high enhancement factor of 5.1 x 10(5) and high detection limit of 10(-10) M. Besides the strong electromagnetic effect of Au NPs, GO sheets play a key in improvement of SERS properties through the strong adsorption of molecules, favorable fluorescence quenching, and chemical enhancement effect.