Surface-enhanced Raman scattering (SERS) study on Rhodamine B adsorbed on different substrates

The SERS signals of Rhodamine B (RhB) adsorbed on Ag, ZnO, and Ag-capped ZnO (ZnO/Ag) substrates were studied. Comparative analysis indicated no significant difference in the positions of the peaks, but the intensities of SERS signals are different. However, abnormal Raman spectrum of RhB (10 −4 M) adsorbed on ZnO was observed, which was different from the normal Raman spectrum distinctly. By assignment of the vibrational bands of abnormal Raman spectrum, it is suggested that the nitrogen atom is primarily adsorbed on the ZnO substrate instead of the xanthene ring.