Surface-enhanced Raman Spectroscopy for Studying the Tensile Structure Between Au@Pd Nanoparticle Interfaces

摘要

When two metals contact each other, the electrons may transfer from one metal to another because of the different work functions. Up to now, it still lacks of methods to reliably monitor such an interaction. Electron transfer between the two metals has been detected by measuring the potential of zero charge (PZC) in an electrochemical interface. Kolb and coworkers1-2 found that the PZC of the Au electrode coated with a thin Pd overlayer changed with the increase of the Pd thickness; however, it is still not conclusive whether it was the result of the change of the work function or due to the different water structure. Surface-enhanced Raman spectroscopy (SERS), on the other hand, is a powerful method to obtain information from the monolayer adsorbed molecules. When the molecules interact with a substrate of different electron structures, the frequencies of some vibration modes of the molecules may sensitively reflect the electronic properties of the substrate. Therefore, we can use some sensitive probe molecules to obtain the electronic properties of the substrate.