Study on surface-enhanced Raman spectroscopy of C60 films on Ag electrodes

The thin films of C-60 on Ag electrodes were studied by in situ surface-enhanced Raman spectroscopy (SERS) in acetonitrile solution and water solution respectively. The influence of C-60 from bulk solution on the SERS of the adsorbed C-60 was removed by pre-forming C-60 films on the electrode. The results indicate that the split of some relevant Raman bands was attributed to the loss of vibrational degeneracy due to the lowering of the C-60 molecular symmetry. Moreover, the surface selection rule was extended because of the influence of the surface electromagnetic field in which some forbidden modes became Raman-active. The results were similar to that of C-60 molecules adsorbed on Ag electrode in the solution of C-60. A weak band at about 348 and 311 cm(-1) was observed for the C-60 films in acetonitrile solution and in aqueous solution respectively, which could be assigned to the interaction of C-60 and Ag electrode surface.